Systems and methods for shunting fluid

ABSTRACT

Systems and methods are provided herein that generally involve shunting fluid, e.g., shunting cerebrospinal fluid in the treatment of hydrocephalus. Self-cleaning catheters are provided which include split tips configured such that pulsatile flow of fluid in a cavity in which the catheter is inserted can cause the tips to strike one another and thereby clear obstructions. Catheters with built-in flow indicators are also provided. Exemplary flow indicators include projections that extend radially inward from the interior surface of the catheter and which include imagable portions (e.g., portions which are visible under magnetic resonance imaging (MRI)). Movement of the flow indicators caused by fluid flowing through the catheter can be detected using MRI, thereby providing a reliable indication as to whether the catheter is partially or completely blocked. Systems and methods for flushing a shunt system are also disclosed herein, as are various systems and methods for opening auxiliary fluid pathways through a shunt system.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/690,389 filed on Apr. 18, 2015, which claims priority to U.S.Provisional Application No. 61/981,699 filed on Apr. 18, 2014, each ofwhich is hereby incorporated herein by reference in its entirety.

FIELD

The present invention relates to systems and methods for shunting fluid,e.g., shunting cerebrospinal fluid in the treatment of hydrocephalus.

BACKGROUND

Shunt systems for transport of body fluids from one region of the bodyto another region are generally known. For example, shunt systems areoften used in the treatment of hydrocephalus to drain excesscerebrospinal fluid (CSF) from the ventricles of the brain. A typicalshunt system includes a one-directional, pressure-controlled valve thatis implanted beneath the skin. A ventricular catheter extends from oneside of the valve to the ventricle. A drain catheter extends from theother side of the valve to a drain site, such as the abdominal cavity.

After implantation and use over extended time periods, shunt systemstend to become clogged in certain individuals. Clogging can occur due toforeign materials which collect in the narrow tubular passageways of theshunt system and in the inlet and outlet openings of such passageways.Consequently, it is often necessary to perform follow-on operations onan individual to remove the clog or replace the entire system. Theinconvenience, cost, and risk of complications associated with thesefollow-on procedures are considerable and undesirable. Accordingly, aneed exists for improved systems and methods for shunting fluid.

SUMMARY

Systems and methods are provided herein that generally involve shuntingfluid, e.g., shunting cerebrospinal fluid in the treatment ofhydrocephalus. Self-cleaning catheters are provided which include splittips configured such that pulsatile flow of fluid in a cavity in whichthe catheter is inserted can cause the tips to strike one another andthereby clear obstructions. Catheters with built-in flow indicators arealso provided. Exemplary flow indicators include projections that extendradially inward from the interior surface of the catheter and whichinclude imagable portions (e.g., portions which are visible undermagnetic resonance imaging (MRI)). Movement of the flow indicatorscaused by fluid flowing through the catheter can be detected using MRI,thereby providing a reliable indication as to whether the catheter ispartially or completely blocked. Systems and methods for flushing ashunt system are also disclosed herein, as are various systems andmethods for opening auxiliary fluid pathways through a shunt system.

In some embodiments, a flusher includes a body that defines acollapsible flush dome; a passive flow path that extends between anupstream port and a downstream port, at least a portion of the flow pathbeing defined by a pinch tube that extends across an exterior surface ofthe flush dome; and a valve having a first position in which the flushdome is not in fluid communication with the upstream port or the passiveflow path and a second position in which the flush dome is in fluidcommunication with the upstream port and the passive flow path; whereinapplication of a force to the pinch tube is effective to collapse thepinch tube to block the passive flow path and to collapse the dome tomove the valve to the second position and flush fluid through theupstream port.

The valve can include a valve body that is compressed against a valveseat by an adjustment disc such that rotation of the adjustment disc iseffective to change a threshold opening pressure of the valve. Theadjustment disc can be threadably mounted in a valve cartridge in whichthe valve body is disposed. At least a portion of the flush dome can bedefined by a refill plate having a refill valve mounted therein. Therefill valve can have a first position in which the passive flow path isnot in fluid communication with the flush dome and a second position inwhich the passive flow path is in fluid communication with the flushdome. Collapsing the flush dome can be effective to hold the refillvalve in the first position. The refill plate can mechanically interlockwith the body. The refill plate can define an outer lip that is receivedwithin a recess formed in the body such that the lip is surrounded on atleast four sides by the body. A longitudinal axis of the body can besubstantially perpendicular to a longitudinal axis of the upstream portand a longitudinal axis of the downstream port. A flush channelextending between the flush dome and the valve can include a connectionformed by a barbed fitting. The flusher can include a ventricle catheterin fluid communication with the upstream port. The catheter can includea primary fluid inlet port through which fluid external to the cathetercan flow into an inner lumen of the catheter; an auxiliary fluid inletport covered by a membrane such that fluid external to the cathetercannot flow through the auxiliary inlet port; and the membrane can beconfigured to rupture when a predetermined threshold force is applied tothe membrane by fluid in the inner lumen of the catheter to open theauxiliary fluid inlet port and allow fluid to flow therethrough. Theauxiliary fluid inlet port can include a rectangular slot with roundedcorners. The flusher can include a stiffening sleeve disposed over themembrane. The stiffening sleeve can include a window that is alignedwith the auxiliary fluid inlet port of the catheter. The stiffeningsleeve can be mounted in a recess formed in the catheter such that theouter surface of the stiffening sleeve sits flush with the outer surfaceof the catheter.

In some embodiments, a flusher includes a body that defines acollapsible flush dome; a passive flow path that extends between anupstream port and a downstream port; and a valve comprising a valve bodycompressed against a valve seat by a threaded adjustment disc, the valvehaving a closed position in which the flush dome is not in fluidcommunication with the upstream port via the valve and an open positionin which the flush dome is in fluid communication with the upstream portvia the valve; wherein a threshold pressure required to transition thevalve from the closed position to the open position is adjustable byrotating the threaded adjustment disc with respect to the body.

In some embodiments, a method of flushing a shunt system includes, in asingle motion, applying a force to a flusher at a single contiguouscontact area to collapse a flush dome of the flusher and to close off aconnection to a downstream portion of the shunt system; whereincollapsing the flush dome is effective to release a cough of pressurizedfluid through an upstream portion of the shunt system. The cough offluid can clear an obstruction from a catheter in fluid communicationwith the flusher. The cough of fluid can open an auxiliary flow paththrough a catheter in fluid communication with the flusher.

In some embodiments, a catheter for shunting fluid built up within askull of a patient is provided that includes an elongate tubular bodyhaving proximal and distal ends, first and second flexible tipsextending from the distal end of the elongate body and having one ormore fluid passageways extending therethrough, a plurality of fluidports formed in the first and second tips, and a coupling memberconfigured to hold the first and second tips in a position adjacent toone another.

The first and second flexible tips can be sized and configured forplacement in a brain ventricle. The coupling member can be or caninclude a peelable sheath disposed around the first and second tips. Thecoupling member can be or can include a seamlessly removable insertionsheath disposed around the first and second tips. The coupling membercan be or can include a bioabsorbable adhesive disposed between thefirst and second tips. The coupling member can be or can include astylet or cannula disposed around the first and second tips. The firstand second tips can each have a D-shaped cross-section. The first andsecond tips can together form a circular cross-section when coupled toone another by the coupling member. The first and second tips can eachhave a circular cross-section. The plurality of fluid ports can beformed in a helical pattern through sidewalls of the first and secondtips. Pulsatile flow of fluid in which the first and second tips aredisposed can be effective to cause the first and second tips to strikeone another, thereby dislodging obstructions from the first and secondtips. The catheter can include a plurality of shrouds, each shroud beingdisposed over a respective one of the plurality of fluid ports. Theplurality of shrouds can be formed as hollow quarter spheres.

At least one of the first and second tips can include an embeddedmicrosensor. The embedded microsensor can be or can include at least oneof an interrogatable sensor, a pressure sensor, a flow sensor, a tiltsensor, an accelerometer sensor, a glutamate sensor, a pH sensor, atemperature sensor, an ion concentration sensor, a carbon dioxidesensor, an oxygen sensor, and a lactate sensor. The embedded microsensorcan be or can include a pressure sensor that supplies an outputindicative of a pressure in the environment surrounding the first andsecond tips to a valve to control a fluid flow rate through the valve.At least one of the first and second tips can contain a quantity of adrug, can be coated with a drug, or can be impregnated with a drug. Thedrug can be or can include at least one of an antibacterial agent, ananti-inflammatory agent, a corticosteroid, and dexamethasone. The firstand second tips can be formed from a polymeric composition.

In some embodiments, a shunt for draining fluid built up within a skullof a patient is provided that includes a catheter having an elongatetubular body having proximal and distal ends, first and second flexibletips extending from the distal end of the elongate body and having oneor more fluid passageways extending therethrough, a plurality of fluidports formed in the first and second tips, and a coupling memberconfigured to hold the first and second tips in a position adjacent toone another. The shunt can further include a skull anchor coupled to theproximal end of the elongate tubular body, the skull anchor including aninjection port through which fluid can be supplied to or withdrawn fromthe elongate tubular body. The shunt can further include a draincatheter extending from the skull anchor, and a one-directional,pressure controlled valve disposed in line with at least one of thecatheter and the drain catheter.

In some embodiments, a method of shunting body fluid is provided thatincludes inserting a catheter having first and second flexible tipsextending from a distal end thereof and coupled to one another into afluid-containing cavity such that fluid can flow out of the cavitythrough the catheter, and decoupling the first and second tips such thatpulsatile flow of fluid within the cavity causes the first and secondtips to strike one another, thereby dislodging obstructions from thefirst and second tips.

Decoupling the first and second tips can include at least one ofremoving a sheath disposed around the first and second tips, removing astylet or cannula disposed around the first and second tips, andexposing a bioabsorbable adhesive disposed between the first and secondtips to the fluid. The method can include adjusting a fluid flow ratethrough a valve in response to an output of a pressure sensor disposedon at least one of the first and second tips.

In some embodiments, a catheter is provided that includes an elongatetubular body having proximal and distal ends and a fluid lumen extendingtherethrough, and a plurality of flow-indicating projections extendingradially inward from an interior surface of the fluid lumen, each of theprojections having an imagable portion. At least the imagable portionsof the projections can be configured to move relative to the fluid lumenwhen fluid is flowing through the fluid lumen and to remain stationaryrelative to the fluid lumen when fluid is not flowing through the fluidlumen.

The projections can each include a first end fixed to the interiorsurface of the fluid lumen and a second end free to move relative to theinterior surface of the fluid lumen. The imagable portions can bedisposed at the second free ends of the projections. The projections canbe formed by advancing the projections through openings pierced througha sidewall of the elongate tubular body and then sealing the openings.The imagable portions can be formed from a radiopaque material. Theimagable portions can be formed from a metallic material. The imagableportions can be formed from a material that is visible under magneticresonance imaging (MRI). The projections can be flexible. Theprojections can be disposed throughout the length of the elongatetubular body. The projections can be grouped in one or more clustersformed at discrete locations within the elongate tubular body.

In some embodiments, a method of determining whether fluid is flowingthrough a fluid lumen of an implanted catheter is provided. The methodcan include capturing one or more images of the catheter and a pluralityof flow-indicating projections extending radially inward from aninterior surface of the fluid lumen, each of the projections having animagable portion. The method can also include determining that fluid isflowing through the fluid lumen when the images indicate that theimagable portions are moving relative to the fluid lumen, anddetermining that fluid is not flowing through the fluid lumen when theimages indicate that the imagable portions are stationary relative tothe fluid lumen. The images can be at least one of magnetic resonanceimages, computed tomography images, positron emission tomography images,and fluoroscopic images.

In some embodiments, a catheter is provided that includes an elongatebody having proximal and distal ends and a plurality of independentfluid lumens extending through at least a portion thereof, and aplurality of fluid openings formed in a sidewall of the elongate body,each fluid opening being in fluid communication with one of theplurality of fluid lumens. The fluid openings can be formed such thatfluid openings that are in fluid communication with different ones ofthe plurality of independent fluid lumens face in different directions.The catheter can include a conical tip formed at the distal end of theelongate body, the conical tip having a plurality of fluid openingsformed therein, each of the fluid openings being in fluid communicationwith one or more of the plurality of fluid lumens.

In some embodiments, a flusher is provided that includes a body havingan upstream port and a downstream port, and a flush channel extendingfrom a ventricle channel and a drain channel to a dome, the ventriclechannel extending from the upstream port to the flush channel and thedrain channel extending from the downstream port to the flush channel.The flusher also includes a valve disposed in the flush channel having afirst position in which the ventricle channel and the drain channel arein fluid communication with one another and the dome is not in fluidcommunication with the ventricle channel or the drain channel via theflush channel, and a second position in which the dome is in fluidcommunication with the ventricle channel via the flush channel and thedrain channel is not in fluid communication with the dome or theventricle channel. The dome is collapsible to move the valve to thesecond position and flush fluid through the ventricle channel.

In some embodiments, a flushing system is provided that includes a flushcomponent having a collapsible dome, a valve component coupled to theflush component by a first catheter and having a flush valve and aflapper valve disposed therein, and a Y adapter coupled to the valvecomponent by a second catheter and coupled to the flush component by athird catheter. The flush valve is configured to open when a pressuredifferential across the flush valve exceeds a predetermined threshold,the flapper valve is configured to open when the flush valve opens toblock fluid flow from the valve component to the Y adapter, and the domeis collapsible to create a pressure differential across the flush valve.

In some embodiments, a flusher is provided that includes a body havingan upstream port and a downstream port, a ventricle channel that extendsfrom the upstream port to a flush valve chamber, a drain channel thatextends from the downstream port to a refill valve chamber, a flushchannel that extends from the flush valve chamber to a dome, a refillchannel that extends from the refill valve chamber to the dome, a bypasschannel that extends from the flush valve chamber to the refill valvechamber, a flush valve disposed in the flush valve chamber andconfigured to allow fluid communication between the flush channel andthe ventricle channel when a pressure differential cross the flush valveexceeds a predetermined threshold, a refill valve disposed in the refillvalve chamber and configured to allow fluid to flow from the bypasschannel into the refill channel and prevent fluid from flowing from therefill channel into the bypass channel, and a bypass valve disposed inthe bypass channel configured to prevent fluid flow through the bypasschannel when the fluid pressure in the bypass channel exceeds apredetermined threshold. The dome is collapsible to force fluid throughthe flush valve and the ventricle channel while causing the bypass valveto close to prevent fluid from being forced through the drain channel.The flusher can include a spring configured to bias the dome to anun-collapsed configuration.

In some embodiments, a catheter is provided that includes a primaryfluid inlet port through which fluid external to the catheter can flowinto an inner lumen of the catheter, and an auxiliary fluid inlet portcovered by a membrane such that fluid external to the catheter cannotflow through the auxiliary inlet port. The membrane is configured torupture when a predetermined threshold force is applied to the membraneby fluid in the inner lumen of the catheter to open the auxiliary fluidinlet port and allow fluid to flow therethrough. The auxiliary fluidinlet port can be or can include a rectangular slot with roundedcorners. The primary fluid inlet port can include at least one slitextending therethrough such that the periphery of the inlet port isconfigured to deform outwards when the catheter is flushed.

The present invention further provides devices, systems, and methods asclaimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be more fully understood from the following detaileddescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a schematic view of a shunt system implanted in a patient;

FIG. 2 is a perspective view of a ventricular catheter and skull anchor;

FIG. 3 is a sectional perspective view of the ventricular catheter ofFIG. 2;

FIG. 4 is a perspective view of a ventricular catheter having flexibletips with circular cross-sections;

FIG. 5 is a perspective view of a ventricular catheter withclog-preventing shrouds;

FIG. 6 is a perspective view of a ventricular catheter with a couplingmember shown in phantom;

FIG. 7 is a perspective view of a ventricular catheter with a conicaltip;

FIG. 8 is a sectional side view of a ventricular catheter withflow-indicating projections disposed therein;

FIG. 9 is a sectional perspective view of a ventricular catheter havingflow-indicating projections disposed therein;

FIG. 10 is a perspective view of a ventricular catheter having multipleindependent fluid lumens;

FIG. 11 is a perspective view of a ventricular catheter having a conicaltip;

FIG. 12 is a sectional view of a flusher with a ball and spring valve;

FIG. 13A is a perspective view of a flush system with a series of valvesand fluid pathways;

FIG. 13B is a sectional view of the flush component of the flush systemof FIG. 13A;

FIG. 13C is a sectional view of the valve component of the flush systemof FIG. 13A;

FIG. 14A is a perspective view of a compact flusher;

FIG. 14B is a sectional plan view of the flusher of FIG. 14A;

FIG. 14C is a sectional profile view of the flusher of FIG. 14A;

FIG. 14D is a perspective view of a modular flusher;

FIG. 14E is a plan view of the flusher of FIG. 14D with portions shownin phantom;

FIG. 14F is a profile view of the flusher of FIG. 14D with portionsshown in phantom;

FIG. 14G is an exploded perspective view of the flusher of FIG. 14D withportions shown in phantom;

FIG. 15A is a plan view of a diaphragm valve disc;

FIG. 15B is a sectional view of a diaphragm valve in an open position;

FIG. 15C is a sectional view of a diaphragm valve in a closed position;

FIG. 15D is a sectional view of another exemplary valve in a closedposition;

FIG. 15E is a sectional view of the valve of FIG. 15D in an openposition;

FIG. 16 is a sectional view of a flusher with a stem;

FIG. 17 is a sectional view of a flusher with a bulb and wedge flappervalve;

FIG. 18 is a sectional view of a flusher with a piston and spring valve;

FIG. 19A is a sectional view of a flusher with a piston and springvalve, shown with the valve in a first position;

FIG. 19B is a sectional view of the flusher of FIG. 19A, shown with thevalve in a second position;

FIG. 20A is a sectional view of a flusher with a lever and linkagevalve, shown with the valve in a first position;

FIG. 20B is a sectional view of the flusher of FIG. 20A, shown with thevalve in a second position;

FIG. 21A is a sectional view of a flusher with a flapper and recessvalve, shown with the valve in a first position;

FIG. 21B is a sectional view of the flusher of FIG. 21A, shown with thevalve in a second position;

FIG. 22 is a sectional view of a flusher with a drain channel that canbe manually occluded;

FIG. 23 is a sectional view of a flusher with a collapsible stem;

FIG. 24 is a sectional view of a flusher with a ball and spring valve;

FIG. 25A is a sectional view of a flusher with a piston and springvalve, shown with the valve in a first position;

FIG. 25B is a sectional view of the flusher of FIG. 25A, shown with thevalve in a second position;

FIG. 26A is a sectional view of a flusher with a coil spring disposedwithin the flush dome;

FIG. 26B is a sectional view of a flusher with a leaf spring disposedwithin the flush dome;

FIG. 27 is a sectional view of a flusher with a stem valve, the stemvalve having a primary flow channel and a retrograde flush flow channel;

FIG. 28A is a perspective view of a catheter having clogged primaryfluid inlet ports with an inset of an auxiliary fluid inlet port after amembrane disposed over the port is ruptured;

FIG. 28B is a plan view of an auxiliary fluid inlet port of the catheterof FIG. 28A after a non-tensioned membrane disposed over the port isruptured;

FIG. 28C is a plan view of an auxiliary fluid inlet port of the catheterof FIG. 28A after a tensioned membrane disposed over the port isruptured;

FIG. 29 is a plan view of a catheter having an auxiliary tip with acylindrical plug;

FIG. 30 is a sectional view of a catheter having a stretchablebulb-shaped distal end;

FIG. 31 is a sectional view of a ball and detent bypass switch;

FIG. 32 is a sectional view of a membrane bypass switch;

FIG. 33 is a perspective view of a push button bypass switch;

FIG. 34 is a sectional view of a split-tip catheter with an auxiliarytip sealed by a membrane;

FIG. 35A is a sectional view of a catheter with a stretchable distal tipshown in a non-stretched position;

FIG. 35B is a sectional view of a catheter with a stretchable distal tipshown in a stretched position;

FIG. 36A is a plan view of a catheter with longitudinal stand-off ribs;

FIG. 36B is a sectional view of the catheter of FIG. 36A;

FIG. 37 is a perspective view of a dual lumen catheter with an auxiliarylumen sealed by a removable stylet;

FIG. 38 is a sectional view of a catheter with alongitudinally-translatable inner sheath;

FIG. 39A is a sectional view of a catheter with conical flap inlet portsshown prior to a flushing operation;

FIG. 39B is a sectional view of the catheter of FIG. 39A after aflushing operation;

FIG. 40A is a sectional view of a split-tip catheter shown prior to aflushing operation;

FIG. 40B is a sectional view of the catheter of FIG. 40A shown after aflushing operation;

FIG. 41 is a sectional view of a catheter with one or more degradablesheaths;

FIG. 42 is a sectional view of a split-tip catheter having a rolled upauxiliary tip;

FIG. 43A is a sectional view of a catheter having a folded-in distal endbefore a flushing operation;

FIG. 43B is a sectional view of the catheter of FIG. 43A after aflushing operation;

FIG. 44A is a sectional view of a catheter having a bellows portionbefore a flushing operation;

FIG. 44B is a sectional view of the catheter of FIG. 44A after aflushing operation;

FIG. 45 is a sectional view of a catheter having one or more blind boresformed in a distal sidewall thereof;

FIG. 46 is a sectional view of a catheter with an arm and fingermechanism;

FIG. 47A is a perspective view of a catheter with a slot-shapedauxiliary hole;

FIG. 47B is a perspective view of an inline catheter component;

FIG. 48A is a plan view of a catheter with cross-slit inlet holes;

FIG. 48B is a plan view of a cross-slit inlet hole not under pressure;

FIG. 48C is a plan view of a cross-slit inlet hole under pressure; and

FIG. 48D is a sectional profile view of a cross-slit inlet hole underpressure.

FIG. 49A is a perspective view of a flusher;

FIG. 49B is an exploded perspective view of the flusher of FIG. 49A;

FIG. 49C is a longitudinal sectional view of the flusher of FIG. 49A;

FIG. 49D is a lateral sectional view of the flusher of FIG. 49A;

FIG. 49E is a perspective view of a valve cartridge of the flusher ofFIG. 49A;

FIG. 49F is a top view of the flusher of FIG. 49A;

FIG. 49G is a bottom view of the flusher of FIG. 49A with a base plateremoved;

FIG. 50A is a perspective view from above of a flusher with a pinch tuberemoved;

FIG. 50B is another perspective view from above of the flusher of FIG.50A;

FIG. 50C is a perspective view from below of the body of the flusher ofFIG. 50A;

FIG. 50D is another perspective view from below of the body of theflusher of FIG. 50A;

FIG. 50E is a longitudinal sectional view of the flusher of FIG. 50A;

FIG. 50F is a perspective view from below of the flusher of FIG. 50A;

FIG. 50G is a perspective view from below of the flusher of FIG. 50Awith a base plate removed;

FIG. 50H is a perspective view from below of the flusher of FIG. 50Awith a flush channel cover removed;

FIG. 50I is a perspective view from below of the flusher of FIG. 50Awith a valve seat removed;

FIG. 51 is a longitudinal sectional view of a flusher;

FIG. 52 is a longitudinal sectional view of another flusher;

FIG. 53 is a longitudinal sectional view of another flusher;

FIG. 54 is a longitudinal sectional view of another flusher;

FIG. 55 is a longitudinal sectional view of another flusher;

FIG. 56A is a schematic diagram of one exemplary arrangement of refilland drain lumens with respect to a flush dome;

FIG. 56B is a schematic diagram of another exemplary arrangement ofrefill and drain lumens with respect to a flush dome;

FIG. 56C is a schematic diagram of another exemplary arrangement ofrefill and drain lumens with respect to a flush dome

FIG. 56D is a schematic diagram of another exemplary arrangement ofrefill and drain lumens with respect to a flush dome;

FIG. 56E is a schematic diagram of another exemplary arrangement ofrefill and drain lumens with respect to a flush dome;

FIG. 56F is a series of sectional views of various pinch tube extrusionprofiles;

FIG. 56G is a sectional view of a multi-component pinch tube;

FIG. 56H is a sectional view of another multi-component pinch tube;

FIG. 57 is a longitudinal sectional view of another flusher;

FIG. 58A is a sectional view of a catheter;

FIG. 58B is an exploded view of the catheter of FIG. 58A;

FIG. 59A is a perspective view of a catheter with a radiopaque banddisposed over an auxiliary flow membrane;

FIG. 59B is a perspective view of a catheter with a radiopaque wiredisposed over an auxiliary flow membrane;

FIG. 60A is a perspective view of an implanted catheter withobstructions blocking primary inlet ports of the catheter;

FIG. 60B is a perspective view of the catheter of FIG. 60A with theobstructions cleared by a flushing operation;

FIG. 60C is a perspective view of the catheter of FIG. 60A with anauxiliary inlet port of the catheter having been opened by a flushingoperation; and

FIG. 61 is a perspective view of a patient with a shunt system implantedtherein.

DETAILED DESCRIPTION

Systems and methods are provided herein that generally involve shuntingfluid, e.g., shunting cerebrospinal fluid in the treatment ofhydrocephalus. Self-cleaning catheters are provided which include splittips configured such that pulsatile flow of fluid in a cavity in whichthe catheter is inserted can cause the tips to strike one another andthereby clear obstructions. Catheters with built-in flow indicators arealso provided. Exemplary flow indicators include projections that extendradially inward from the interior surface of the catheter and whichinclude imagable portions (e.g., portions which are visible undermagnetic resonance imaging (MRI)). Movement of the flow indicatorscaused by fluid flowing through the catheter can be detected using MRI,thereby providing a reliable indication as to whether the catheter ispartially or completely blocked. Systems and methods for flushing ashunt system are also disclosed herein, as are various systems andmethods for opening auxiliary fluid pathways through a shunt system.

Certain exemplary embodiments will now be described to provide anoverall understanding of the principles of the structure, function,manufacture, and use of the methods, systems, and devices disclosedherein. One or more examples of these embodiments are illustrated in theaccompanying drawings. Those skilled in the art will understand that themethods, systems, and devices specifically described herein andillustrated in the accompanying drawings are non-limiting exemplaryembodiments and that the scope of the present invention is definedsolely by the claims. The features illustrated or described inconnection with one exemplary embodiment may be combined with thefeatures of other embodiments. Such modifications and variations areintended to be included within the scope of the present invention.

Shunt Systems

FIG. 1 illustrates one exemplary embodiment of a shunt system 100. Thesystem generally includes a ventricular catheter 102, an anchor 104, anda drain catheter 106 with an inline valve 108. In some embodiments, theshunt system 100 can be used to treat hydrocephalus by implanting theventricular catheter 102 such that a distal end of the catheter isdisposed within a brain ventricle 110 of a patient 112. The anchor 104can be mounted to the patient's skull, beneath the skin surface, and thedrain catheter 106 can be implanted such that the proximal end of thedrain catheter is disposed within a drain site, such as the abdominalcavity. The valve 108 can be configured to regulate the flow of fluidfrom the ventricle 110 to the drain site. For example, when fluidpressure in the ventricle exceeds the opening pressure of the valve 108,the valve can be configured to open to allow excess fluid to drain outof the ventricle 110. When the fluid pressure drops to an acceptablelevel, the valve 108 can be configured to close, thereby stoppingfurther draining of fluid.

It will be appreciated that the arrangement and features of the system100 shown in FIG. 1 is merely exemplary, and that several othervariations are possible. For example, the valve 108 can be disposeddistal to the anchor 104 instead of proximal thereto as shown. In otherembodiments, the valve 108 can be integral to the anchor 104 or theanchor can be omitted altogether.

The shunt system 100 can include any of a variety of catheters,including single lumen catheters, multi-lumen catheters, and split-tipcatheters. As shown in FIG. 2, the illustrated split-tip ventricularcatheter 102 includes an elongate tubular body 114 having proximal anddistal ends 114P, 114D. The catheter 102 also includes first and secondflexible tips 116 extending from the distal end 114D of the body 114.While two tips 116 are illustrated, it will be appreciated that thecatheter 102 can include any number of tips (e.g., three, four, five,six, and so forth). Each of the first and second tips 116 can have oneor more discrete or independent fluid passageways extendingtherethrough. The fluid passageways can remain separate from one anotherthroughout the entire length of the catheter 102, or one or more of thefluid passageways can merge, e.g., at the junction between the first andsecond tips 116 and the elongate body 114.

A plurality of fluid ports 118 can be formed in each of the first andsecond tips 116. The ports 118 can be arranged in any of a variety ofconfigurations. For example, the fluid ports 118 can be arranged in ahelical pattern through the sidewalls of the first and second tips 116.Alternatively, or in addition, some or all of the fluid ports 118 can bearranged in a linear pattern, in a circular pattern, and/or as openterminal distal ends of the first and second tips 116. In an exemplaryembodiment, each of the first and second tips can include one to twelvefluid ports. The diameter of the fluid ports can be between about 0.1 mmand about 2.5 mm. The cross-sectional area of the fluid ports can bebetween about 1 mm² and about 3 mm². In some embodiments, the fluidports can be progressively larger in diameter towards the distal end ofthe catheter to equalize or balance the flow through the ports. Sizingthe ports in this manner can prevent localized areas of high or low flowthat might otherwise occur with equally-sized ports, and thereby reducethe likelihood of a clog developing.

One or more of the tips 116 can include an embedded sensor 120. Thesensor 120 can include temperature sensors, flow sensors, pH sensors,pressure sensors, oxygen sensors, tension sensors, interrogatablesensors, tilt sensors, accelerometer sensors, glutamate sensors, ionconcentration sensors, carbon dioxide sensors, lactate sensors,neurotransmitter sensors, or any of a variety of other sensor types, andcan provide feedback to a control circuit which can in turn regulate thedrainage of fluid through the system 100 based on one or more sensedparameters. A sensor wire (not shown) can extend from the sensor 120 toan implantable control unit, and/or the sensor can wirelesslycommunicate the sensor output to an extracorporeal control unit. Theembedded microsensor 120 can be a pressure sensor that supplies anoutput indicative of a pressure in the environment surrounding the firstand second tips 116 to the valve 108 to control a fluid flow ratethrough the valve.

At least a portion of the ventricular catheter 102 (e.g., the first andsecond tips 116) or any other component of the system 100 can contain orcan be impregnated with a quantity of a drug. Alternatively, or inaddition, a surface of said portion can be coated with a drug. Exemplarydrugs include anti-inflammatory components, anti-bacterial components,drug permeability-increasing components, delayed-release coatings, andthe like. In some embodiments, one or more portions of the system 100can be coated or impregnated with a corticosteroid such as dexamethasonewhich can prevent swelling around the implantation site and disruptionsto the fluid drainage function that can result from such swelling.

As shown in FIG. 3, the first and second tips 116 can each have aD-shaped cross-section. In other words, the first and second tips 116can each have a substantially planar sidewall 122 and a substantiallyhemi-cylindrical sidewall 124. The orientation of the D-shape of thefirst tip can be opposite to that of the second tip, such that the firstand second tips 116 together form a circular cross-section when they arecoupled to one another or when they longitudinally abut one another. Thefirst and second tips 116 can also have other cross-section shapes. Forexample, as shown in FIG. 4, the first and second tips 116 can each havea circular cross-section.

The ventricular catheter 102, and in particular the first and secondflexible tips 116, can be sized and configured for placement in a brainventricle. For example, in some embodiments, the body 114 of theventricular catheter 102 can have a length between about 2 cm and about15 cm and an outside diameter between about 1 mm and about 5 mm. In someembodiments, the first and second tips 116 can have a length betweenabout 3 cm and about 15 cm and/or a cross-sectional area between about 1mm² and about 7 mm².

One or more of the fluid ports 118 in the ventricular catheter 102 caninclude shrouds or covers 126 to reduce the tendency for the port tobecome clogged. For example, as shown in FIG. 5, the catheter 102 caninclude shrouds 126 that extend at least partially over the fluid ports118 formed in each tip 116. In some embodiments, the shrouds 126 can beformed as sections of a hollow sphere, e.g., hollow quarter spheres asshown. The shrouds 126 can have a variety of other shapes, includingsections of a cylinder, sections of a cube, and so forth. The shrouds126 can be placed in any of a variety of orientations. For example, theshrouds 126 can be placed in random orientations, in alternatingorientations, in a repetitive sequence of orientations, and so forth. Inoperation, the shrouds 126 can prevent ingrowth of choroid plexus intothe fluid ports 118 and/or accumulation of other tissue, debris, ormaterial that might block the fluid ports.

As shown in FIG. 6, the ventricular catheter 102 can include a couplingmember 128 configured to hold the first and second tips 116 in aposition adjacent to one another, e.g., in longitudinal abutment withone another. The coupling member 128 can be disposed around the firstand second tips 116 as shown, and thereby configured to retain the tipsin a position proximate to one another. Exemplary coupling members 128can include a seamlessly removable insertion sheath, a peelable sheath,a stylet, or a cannula disposed around the first and second tips 116 andaccessible for removal from a proximal end of the catheter 102. Thecoupling member can also be in the form of an adhesive disposed betweenthe first and second tips 116. For example, in the case of D-shaped tips116, the planar sidewalls 122 of the first and second tips can beadhered to one another. The adhesive or at least the adhesive strengththereof can be configured to degrade when the adhesive is exposed toconditions within the body of a patient (e.g., certain temperatures,pHs, chemical compositions, and so forth). In exemplary embodiments, theadhesive is biocompatible and bioabsorbable and configured to rapidlydegrade when exposed to cerebrospinal fluid in a patient's ventricle.Exemplary adhesives include, e.g., polylactides, polyglycolides,polylactones, polyorthoesters, polyanhydrides, proteins, starches,sugars and copolymers and/or combinations thereof.

The distal-most tip of the catheter 102 can have a variety of shapes andconfigurations. For example, the distal ends of the first and secondtips 116 can be open or closed, or can be primarily closed with one ormore openings formed therein. By way of further example, the distal endsof the first and second tips 116 can together form a section of a sphere(e.g., as shown in FIG. 2), can be straight cut to form a blunt end(e.g., as shown in FIG. 6), can be slash cut, or can form a section of acone (e.g., as shown in FIG. 7).

The ventricular catheter 102 can include various features for indicatingwhether or to what degree fluid is flowing through the catheter. Suchfeatures can advantageously allow for accurate detection or confirmationof blockages or reduced flow conditions within the catheter 102, withoutrequiring removal of the catheter. For example, as shown in FIG. 8, thecatheter 102 can include a plurality of flow-indicating projections 130disposed therein. The projections can be formed from any of a variety offlexible materials to allow them to flex or bend. The projections canextend radially inward from an interior surface 132 of a fluid lumen ofthe catheter 102, such that a first end 134 of each projection 130 isfixed to the interior surface 132 and a second end 136 of eachprojection is free to move relative to the interior surface when theprojection flexes or bends.

The projections 130 can be imagable or can include one or more imagableportions. For example, the projections 130 can include imagable portions138 disposed at the second free ends 136 of the projections. Theimagable portions 138 can be visible under one or more imagingtechniques, such as magnetic resonance imaging (MRI), computedtomography (CT) imaging, positron emission tomography (PET) imaging, andfluoroscopic imaging. The imagable portions 138 can thus be formed froma radiopaque material, a metallic material, a material that is visibleunder magnetic resonance imaging, or any of a variety of other materialsvisible under the imaging techniques listed above. As shown in FIG. 9,in some embodiments, the entirety of each projection 130 can beimagable.

The projections 130 can be coupled to the catheter 102 by piercing theprojections through a sidewall of the catheter and advancing theprojections through the pierced opening. The opening can then be sealedusing any of a variety of sealing compounds, including silicone glue orother adhesives. It will be appreciated that this is only one of manyways of fixing the projections 130 to the catheter 102, and thereforethat various other techniques can be used instead or in addition.

The projections 130 can be disposed throughout the length of thecatheter 102 (e.g., in the elongate tubular body 114 and/or the distaltips 116 of the catheter), or can be grouped in one or more clustersformed at discrete locations within the catheter. The density of theprojections 130 (e.g., the number of projections disposed in a givensurface area of the interior of the catheter) can be selected based onthe size of the fluid lumen in which the projections are disposed.

In use, at least the imagable portions 138 of the projections 130 can beconfigured to move relative to the fluid lumen when fluid is flowingthrough the fluid lumen and to remain stationary relative to the fluidlumen when fluid is not flowing through the fluid lumen. The projections130 can thus act as reef or thread-like structures that sway back andforth as fluid flows through the catheter 102. This movement of theprojections 130 can be observed using the imaging techniques listedabove to assess whether and to what degree fluid is flowing through theshunt system 100.

FIG. 10 illustrates another exemplary embodiment of a ventricularcatheter 202. Except as indicated below, the structure and operation ofthe catheter 202 is identical to that of the catheter 102 describedabove, and therefore a detailed description thereof is omitted here forthe sake of brevity. Instead of multiple flexible tips, the multi-lumencatheter 202 includes a single tip 216 with a plurality of independentfluid lumens 240 extending therethrough. The fluid lumens 240 can remainindependent throughout the length of the catheter 202, or can merge intoone or more common fluid lumens at a location spaced a distance from thedistal end of the catheter. While three fluid lumens 240 are shown, itwill be appreciated that virtually any number of fluid lumens can beincluded. For example, the catheter 202 can include between two and fivefluid lumens 240. Each of the independent fluid lumens 240 can includeone or more fluid openings 218 formed in a sidewall thereof throughwhich fluid to be shunted can flow into the fluid lumens. The distalends of the fluid lumens 240 can be open as shown, or can be fully orpartially closed. In some embodiments, the distal end of the catheter202 can form a section of a sphere or cone 242, e.g., as shown in FIG.11, which can have one or more fluid openings 218 formed therein.Provision of multiple independent fluid lumens 240 can advantageouslyprovide redundancy in the event that one or more of the fluid lumensbecomes clogged. Further, if the source of clogging is directional,i.e., the source arrives at the catheter in predominately one direction,then it is more likely that if one lumen becomes clogged, the otherlumens will continue to operate as the openings leading into thoselumens will be facing in different directions from the lumen that becameclogged. Also, providing multiple fluid lumens 240 allows for a flowrate comparable to that of a single lumen catheter while permitting thecross-sectional area of each fluid lumen 240 to be made small ascompared to a single lumen catheter. The smaller dimensions of themultiple lumens 240 can prevent foreign material or choroid plexusingrowth from entering the lumen and thereby reduce the potential forclogging.

The catheters 102, 106, 202 and the coupling member 128 can be formedfrom any of a variety of materials, including polymeric compositions,parylene compositions, silastic compositions, polyurethane compositions,PTFE compositions, silicone compositions, and so forth.

Referring again to FIGS. 1 and 2, the system 100 can include an anchor104 to which the ventricular catheter 102 can be coupled. The anchor 104can be secured to the patient's skull, beneath the skin, to secure theproximal end of the ventricular catheter 102 and to provide access tothe system 100. For example, the anchor 104 can include a reservoir influid communication with the ventricular catheter 102 and covered by aseptum 144. A needle can be used to pierce the skin and the septum 144and supply fluid to the reservoir and to extract fluid from thereservoir. Fluid communication between the reservoir and the patient'sventricle 110 via the ventricular catheter 102 can be used to inject oneor more drugs, therapeutic agents, etc. into the ventricle. Inembodiments in which the catheter 102 includes multiple independentlumens, one or more lumens can be dedicated for drug delivery to theventricle 110 while one or more other lumens can be dedicated for fluiddrainage from the ventricle.

In the illustrated embodiment, the anchor 104 is substantiallydisk-shaped and includes a concave distal surface 146 configured tosubstantially conform to the contour of the patient's skull. Theproximal surface 148 of the anchor 104 can include a retaining ring 150that extends around the circumference of the anchor and holds the septum144 in place. The ventricular catheter 102 can couple to a center pointof the distal surface 146. A drain catheter 106 can extend laterally outfrom the anchor 104 to the downstream valve 108 and, ultimately, to thedrain site. The anchor 104 can thus provide a rigid coupling between oneor more implanted catheters 102, 106 and facilitate a 90 degree turn inthe fluid path out of the ventricle 110.

The drain catheter 106 extending out of the anchor 104 can be coupled toa valve 108 configured to selectively open to release fluid from theventricle 110. In general, the valve 108 can include an inlet port, anoutlet port, and a biased flapper disposed therebetween. When pressureexceeds the bias strength of the flapper, the flapper can open to allowfluid communication between the inlet port and the outlet port. Thevalve 108 can also be adjustable, e.g., via an externally-appliedmagnetic field. Shunt valves with adjustable pressure settings are wellknown in the art, and are disclosed for example in U.S. Pat. No.3,886,948, issued on Jun. 3, 1975 and entitled “VENTRICULAR SHUNT HAVINGA VARIABLE PRESSURE VALVE,” the entire contents of which areincorporated herein by reference.

The valve 108 can be disposed inline relative to the drain catheter 106,e.g., such that a first portion of the drain catheter 106 is fluidlycoupled to the inlet port of the valve 108 and a second portion of thedrain catheter 106 is fluidly coupled to the outlet port of the valve108. The drain catheter 106 can thus be conceptualized as two separatecatheters, one extending between the anchor 104 and the valve 108 andanother extending between the valve and the drain site. The draincatheter 106 can extend such that its proximal end is disposed within adrain site in the patient's body, e.g., the abdominal cavity. The draincatheter 106 can be a traditional cylindrical catheter having a singlefluid lumen extending therethrough. Alternatively, the drain catheter106 can include a plurality of discrete fluid lumens extending along atleast a portion of its length. The proximal end of the drain catheter106 can have a split-tip design and/or can otherwise be configured inthe same manner as the distal end of the ventricular catheters 102, 202described above.

In use, the shunt system 100 can be used to transfer fluid from onelocation to another location. When used in a patient's body, the shuntsystem 100 can be used to treat any of a variety of diseases,conditions, or ailments. For example, the system 100 can be used totreat hydrocephalus and/or to shunt fluid built up within a patient'sskull by implanting the ventricular catheter 102 such that a distal endof the catheter is disposed within a brain ventricle 110 of the patient112. The anchor 104 can be mounted to the patient's skull, beneath theskin surface, and the drain catheter 106 can be implanted such that theproximal end of the drain catheter is disposed within a drain site, suchas the abdominal cavity.

Once the distal end of the ventricular catheter 102 is disposed withinthe ventricle 110, the coupling member 128 can be removed (or permittedto degrade in the case of an adhesive) to decouple the first and secondtips 116 from one another and allow the tips to separate. As notedabove, the coupling member 128 can be or can include a peelable sheath,a stylet, or a cannula which can be accessible for removal from aproximal end of the catheter 102. In other words, the coupling member128 can be pulled proximally by a surgeon or other user to remove thecoupling member once the distal tip of the catheter 102 is placed in thedesired location.

Once decoupled, pulsatile flow of fluid within the ventricle 110 can beeffective to cause the first and second tips 116 to strike one another.The forces applied to the tips 116 as a result of such striking candislodge obstructions from the first and second tips or the fluid ports118 or passageways thereof, thereby preventing, reducing, or alleviatingclogs. It will be appreciated that the relatively continuous pulsatileflow of fluid can persist throughout the term of treatment, providing anautomatic self-cleaning and anti-clogging functionality.

As in a typical shunt system, when fluid pressure in the ventricle 110exceeds the opening pressure of the valve 108, the valve can beconfigured to open to allow excess fluid to drain out of the ventricle.When the fluid pressure drops to an acceptable level, the valve 108 canbe configured to close, thereby stopping further draining of fluid. Insome embodiments, the output of a sensor 120 (e.g., a pressure sensor)disposed in or on one of the first and second tips 116 can be used tocontrol operation of the valve 108. For example, an opening pressure,fluid flow rate, or other property of the valve 108 can be adjusted inresponse to the output of a pressure sensor 120.

In embodiments which include flow indicating features 130, adetermination can be made as to whether or to what degree fluid isflowing through the fluid lumen. For example, one or more images (e.g.,MRI, CT, PET, or the like) of a catheter 102 and a plurality offlow-indicating projections 130 disposed therein can be captured. Anobserver can then view the images and determine whether and to whatdegree the projections 130 are moving. For example, when the imagesindicate that the imagable portions 138 of the projections 130 aremoving relative to the fluid lumen, it can be determined that fluid isflowing through the fluid lumen. Likewise, when the images indicate thatthe imagable portions 138 are stationary relative to the fluid lumen, itcan be determined that fluid is not flowing through the fluid lumen andthat there may be a blockage or obstruction in the shunt system.

Flushers

In some embodiments, the shunt system 100 can include a flusher forclearing obstructions from the shunt system or for opening auxiliaryfluid paths through the shunt system. The flusher can be disposedbetween the ventricular catheter 102 and the anchor 104, between theanchor 104 and the valve 108, or between the valve 108 and the draincatheter 106. The flusher can also be formed integrally with any of theventricular catheter 102, the anchor 104, the valve 108, and the draincatheter 106. FIGS. 12-27 and 49A-57 illustrate various exemplaryflusher embodiments that can be used with a shunt system (e.g., with theshunt system 100 described above).

FIG. 12 illustrates an exemplary embodiment of a flusher 1200 with aball and spring valve 1202. The flusher includes a body 1204 with anupstream port 1206 configured to be coupled to or placed in fluidcommunication with a ventricular catheter and a downstream port 1208configured to be coupled to or placed in fluid communication with adrain catheter. The flusher 1200 also includes a dome 1210 that can beactuated, e.g., by exerting downward finger pressure on the dome througha patient's skin, to collapse or compress the dome and expel fluidtherefrom. A network of fluid channels is formed in the body of theflusher, and includes a ventricle channel 1212, a drain channel 1214, aflush channel 1216, and a refill channel 1218. The ventricle channel1212 extends from the upstream port 1206 to the flush channel 1216. Thedrain channel 1214 extends from the downstream port 1208 to the flushchannel 1216. The flush channel 1216 extends from the ventricle anddrain channels 1212, 1214 to the dome 1210. The refill channel 1218extends from the ventricle channel 1212 to the dome 1210. It will beappreciated, however, that in other embodiments the refill channel 1218can extend from the drain channel 1214 to the dome 1210. A one-way orcheck valve 1220 is disposed in the refill channel 1218. The valve 1220is configured to prevent fluid from flowing from the dome 1210 to theventricle channel 1212 through the refill channel, but allows fluid toflow from the ventricle channel to the dome through the refill channel.

The ball and spring valve 1202 is disposed in the flush channel 1216 tocontrol fluid flow through the flusher 1200. The valve 1202 has at leasta first position in which the ball portion of the valve 1222 seals theflush channel 1216 between the dome 1210 and the ventricle and drainchannels 1212, 1214, such that the dome is not in fluid communicationwith the ventricle and drain channels through the flush channel. Theball 1222 can be formed from rubber, silicone, polyurethane, or othermaterials that can provide a seal between the ball and the flush channel1216. The ball 1222 can also be sized to fit within the flush channel1216 in an interference fit to enhance the seal and control the amountof force required to move the ball. In the first position, the ventricleand drain channels 1212, 1214 are in fluid communication with oneanother such that fluid can flow freely from the upstream port 1206 tothe downstream port 1208.

The valve 1202 also has at least a second position in which the ballportion of the valve 1222 seals the drain channel 1214 and in which thedome 1210 is placed in fluid communication with the ventricle channel1212 via the flush channel 1216. In particular, the ball portion of thevalve 1222 can be seated in a spherical valve seat 1224 formed at thejunction of the drain channel 1214 and the flush channel 1216. When theball 1222 is seated in the valve seat 1224, fluid communication betweenthe drain channel 1214 and the flush channel 1216 and between the drainchannel 1214 and the ventricle channel 1212 is cut off. In addition, aclearance space is formed between the ball 1222 and the sidewall of theflush channel 1216 when the ball moves into the valve seat 1224,unsealing the flush channel and placing the dome 1210 in fluidcommunication with the ventricle channel 1212. The spring portion 1226of the valve biases the ball 1222 towards the first position.

In use, the flusher 1200 generally has two operating modes. In a normaloperating mode, the ball 1222 is disposed in the first position due tothe bias of the spring 1226, and fluid is allowed to flow freely fromthe upstream port 1206 to the downstream port 1208. When the flusher1200 is implanted in a patient as part of a shunt system, fluid is freeto flow from the ventricle and through the flusher to a valve or draincatheter disposed downstream from the flusher. In the normal operatingmode, the dome 1210 remains filled with fluid previously supplied to thedome through the refill channel 1218.

In a flush operating mode, a force is exerted on the dome 1210 tocollapse the dome and displace fluid therefrom into the flush channel1216. This causes the pressure above the ball 1222 to increase until theforce of fluid acting on the top of the ball exceeds the spring forceexerted on the bottom of the ball by the bias spring 1226 and theinterference fit between the ball and the flusher channel 1216, at whichpoint the ball moves from the first position to the second position. Insome embodiments, the pressure required to move the ball 1222 from thefirst position to the second position is about 40 psig. When the ballmoves to the second position, the pressurized fluid is suddenlyreleased, resulting in an upstream “cough” or flush of fluid backthrough the ventricle channel 1212, which can be effective to clearobstructions from a ventricle catheter or other upstream component ofthe shunt system, or to open auxiliary flow paths as described furtherbelow. After the cough of fluid is released, the spring 1226 biases theball 1222 back to the first position and the force applied to the dome1210 is removed. Fluid flow through the flusher 1200 in the downstreamdirection then resumes, with a portion of the fluid flow divertingthrough the refill channel 1218 to refill the dome 1210 with fluid andreturn the dome to a non-collapsed configuration. The size of the refillchannel 1218 can be selected to control the rate at which the dome 1210is refilled. For example, the cross-sectional area of the refill channel1218 can be made small to choke the flow of fluid into the dome 1210. Inembodiments in which the dome 1210 has resilient properties, this canadvantageously prevent the dome from quickly springing back to thenon-collapsed configuration and generating a reflux action in whichdebris or obstructions cleared by a flushing operation are sucked backinto the shunt system.

The flusher 1200 thus facilitates generation and application of a highpressure cough of fluid which flushes the ventricle side of the shuntsystem only. The ball and spring valve 1202 prevents the cough of fluidfrom travelling through the drain side of the shunt system. In otherembodiments, however, the flusher 1200 can be configured to flush thedrain side of the system instead or in addition.

FIGS. 13A-13C illustrate an exemplary embodiment of a dual lumen flushsystem 1300. The system 1300 includes a flush component 1302, a valvecomponent 1304, and a Y adapter 1306. The system 1300 also includes afirst catheter 1308 that extends from the valve component to the flushcomponent, a second catheter 1310 that extends from the valve componentto the Y adapter, and a third catheter 1312 that extends from the flushcomponent to the Y adapter. While three separate componentsinterconnected by catheters are shown and described, it will beappreciated that any two or more of the components can be integrated ina single package with the catheters that would ordinarily extend betweensaid components also being integrated into the package as built-in fluidchannels.

As shown in FIG. 13B, the flush component 1302 includes a body 1314 witha valve component port 1316 configured to be coupled to the valvecomponent 1304 via the first catheter 1308 and a refill port 1318configured to be coupled to the Y adapter 1306 via the third catheter1312. The flush component 1302 also includes a dome 1320 that can beactuated, e.g., by exerting downward finger pressure on the dome througha patient's skin, to expel fluid from the dome. A network of fluidchannels is formed in the body 1314 of the flush component 1302, andincludes a valve component channel 1322, a refill channel 1324, and aflush channel 1326. The valve component channel 1322 extends from thevalve component port 1316 to a cavity 1328 in which an umbrella-typeone-way valve 1330 is disposed. The refill channel 1324 extends from thecavity 1328 to the refill port 1318. The flush channel 1326 extends fromthe dome 1320 to the valve component channel 1322. The one-way valve1330 prevents fluid from flowing from the valve component channel 1322to the refill channel 1324 through the cavity 1328, and allows fluid toflow from the refill channel to the valve component channel through thecavity.

As shown in FIG. 13C, the valve component 1304 includes a body 1332 witha flush component port 1334 configured to be coupled to the flushcomponent 1302 via the first catheter 1308, an upstream port 1336configured to be coupled to or placed in fluid communication with aventricular catheter, and a downstream port 1338 configured to becoupled to the Y adapter 1306 via the second catheter 1310. The flushcomponent port 1334 is coupled to an upper chamber 1340 defined by apressure dome. The upper chamber 1340 is separated from a lower chamber1342 by an umbrella valve 1344 and a flapper valve 1346 to control fluidflow through the flush system 1300. The flapper valve 1346 can havevarious configurations. In some embodiments, the flapper valve 1346includes an integral living hinge about which the flapper valve pivotsto open and close. In other embodiments, the flapper valve 1346 iscoupled to the valve component body 1332 by a pivot pin about which theflapper valve pivots to open and close.

The valve component 1304 has a first configuration in which the umbrellavalve 1344 and the flapper valve 1346 are both closed and the upstreamport 1336 of the valve component is in fluid communication with thedownstream port 1338. In the first configuration, fluid can flow freelyfrom the upstream port 1336 to the downstream port 1338 and through theY adapter 1306 (e.g., to a drain catheter).

The valve component 1304 also has a second configuration in which theumbrella valve 1344 opens to place the upper chamber 1340 in fluidcommunication with the lower chamber 1342 and the flapper valve 1346hinges open to block fluid communication between the lower chamber 1342and the downstream port 1338.

In use, the flush system 1300 generally has two operating modes. In anormal operating mode, the valve component 1304 is in the firstconfiguration and fluid is allowed to flow freely from the upstream port1336 to the downstream port 1338 and through the Y adapter 1306. Whenthe flush system 1300 is implanted in a patient as part of a shuntsystem, fluid is free to flow from the ventricle through the flushsystem to a valve or drain catheter disposed downstream from the flushsystem. In the normal operating mode, the dome 1320 remains filled withfluid previously supplied to the dome through the refill channel 1324.

In a flush operating mode, a force is exerted on the dome 1320 tocollapse the dome and displace fluid therefrom into the flush channel1326 and the valve component channel 1322. The one-way valve 1330prevents fluid from being displaced from the dome into the refillchannel 1324. The pressure in the upper chamber 1340 of the valvecomponent 1304 increases until the force of fluid acting on the top ofthe umbrella valve 1344 exceeds the popping threshold of the valve, atwhich point the valve component 1304 transitions to the secondconfiguration. In some embodiments, the pressure required to open theumbrella valve 1344 is about 40 psig, meaning that the pressure abovethe valve must exceed the pressure below the valve by at least 40 psigfor the valve to open. When the umbrella valve 1344 opens, the pressureis applied to the top of the flapper valve 1346, causing it to hingeopen and rotate counterclockwise about a hinge axis (indicated by thearrow A1), until a domed portion of the flapper valve 1346 contacts theentrance to the downstream port 1338 and blocks fluid communicationbetween the lower chamber 1342 and the downstream port. The pressurizedfluid is also suddenly released into the lower chamber 1342, resultingin an upstream “cough” or flush of fluid back through the upstream port1336, which can be effective to clear obstructions from a ventriclecatheter or other upstream component of the shunt system. After thecough of fluid is released, a biasing force (e.g., generated by a biasspring, resilient materials, or hydraulic action) causes the flappervalve 1346 and the umbrella valve 1344 to close. As a result, fluidcommunication is restored between the upstream and downstream ports1336, 1338 of the valve component. Fluid flow through the flush system1300 in the downstream direction then resumes, with a portion of thefluid flow through the Y adapter 1306 diverting through the thirdcatheter 1312 and into the refill channel 1324 of the flush component1302 to refill the dome 1320 through the one-way valve 1330.

In some embodiments, the third catheter 1312 can be larger incross-sectional area than the catheter extending from a downstream portof the Y adapter 1306, such that fluid preferentially flows through thethird catheter to refill the dome 1320 before flowing out of the Yadapter to downstream components of the shunt system. For example, thedownstream catheter can have an inside diameter of about 0.050 inchesand the third catheter 1312 can have an inside diameter of about 0.100inches to about 0.150 inches.

The size of the flush channel 1326, or downstream channels such as thethird catheter 1312, the refill port 1318, or the refill channel 1324,can be selected to control the rate at which the dome 1320 is refilled.For example, the cross-sectional area of the flush channel 1326 can bemade small to choke the flow of fluid into the dome 1320. In embodimentsin which the dome 1320 has resilient properties, this can advantageouslyprevent the dome from quickly springing back to the non-collapsedconfiguration and generating a reflux action in which debris orobstructions cleared by a flushing operation are sucked back into theshunt system.

The flush system 1300 thus facilitates generation and application of ahigh pressure cough of fluid which flushes the ventricle side of theshunt system only. The flapper valve 1346 prevents the cough of fluidfrom travelling through the drain side of the shunt system.

FIGS. 14A-14C illustrate another exemplary embodiment of a flusher 1400.The flusher 1400 includes a body 1404 with an upstream port 1406configured to be coupled to or placed in fluid communication with aventricular catheter and a downstream port 1408 configured to be coupledto or placed in fluid communication with a drain catheter. The flusheralso includes a dome 1410 that can be actuated, e.g., by exertingdownward finger pressure on the dome through a patient's skin, to expelfluid from the dome. The flusher body 1404 also includes a cylindricalsidewall 1402 that extends around the circumference of the dome base andhas a height that is approximately equal to the maximum height of thedome 1410. The sidewall 1402 can protect the dome 1410 from inadvertentactuation (e.g., when a patient with the flusher 1400 implanted beneaththeir scalp lies down, pressing the flusher against a surface). Anetwork of fluid channels is formed in the body 1404 of the flusher, andincludes a ventricle channel 1412, a drain channel 1414, a flush channel1416, a refill channel 1418, and a bypass channel 1420.

The ventricle channel 1412 extends from the upstream port 1406 to aflush valve chamber 1422 in which a flush valve 1424 configured toselectively place the flush channel 1416 in fluid communication with theventricle channel is disposed. The drain channel 1414 extends from thedownstream port 1408 to a refill valve chamber 1426 in which a refillvalve 1428 configured to selectively place the drain channel in fluidcommunication with the refill channel 1418 is disposed. The bypasschannel 1420 extends from the refill valve chamber 1426 to the flushvalve chamber 1422 and includes an inline bypass valve 1430 configuredto control fluid communication through the bypass channel. The refillchannel 1418 and the flush channel 1416 are in fluid communication withthe interior of the dome 1410.

The illustrated refill valve 1428 is an umbrella-type check valve,though other one-way valves can be used instead or in addition. Therefill valve 1428 is configured to allow fluid flow from the drainchannel 1414 into the refill channel 1418 and to prevent fluid flow fromthe refill channel into the drain channel.

The illustrated flush valve 1424 is an umbrella-type check valve, thoughother one-way valves can be used instead or in addition. The flush valve1424 is configured to allow fluid flow from the flush channel 1416 intothe ventricle channel 1412 and to prevent fluid flow from the ventriclechannel into the flush channel. The flush valve 1424 is configured toopen only when a predetermined differential pressure threshold isreached across the valve. For example, the flush valve 1424 can beconfigured such that the valve only opens when the pressure in the flushchannel 1416 is at least 40 psig greater than the pressure in theventricle channel 1412.

The illustrated bypass valve 1430 is a ball and socket valve, thoughother valve types can be used instead or in addition. The bypass valve1430 is configured to automatically control fluid communication throughthe bypass channel 1420. When low pressure fluid flow in the directionof the arrow A2 exists in the bypass channel 1420 (e.g., when normalventricular draining is taking place), the ball 1432 moves away from aseat 1434, and fluid is free to flow from the ventricle channel 1412 tothe drain channel 1414, around the ball. When high pressure fluid flowin the direction of the arrow A2 exists in the bypass channel 1420(e.g., when the pressure in the ventricle channel 1412 spikes as aflushing cough is emitted through the flush valve 1424), the ball 1432moves into engagement with the seat 1434, sealing off the bypass channel1420 and preventing fluid flow from the ventricle channel to the drainchannel 1414. The bypass valve 1430 thus has a first position in whichthe ventricle channel 1412 is in fluid communication with the drainchannel 1414 and a second position in which the ventricle channel is notin fluid communication with the drain channel. The bypass valve 1430 isconfigured to automatically move from the first position to the secondposition in response to a flushing cough emitted through the flush valve1424.

The flusher 1400 can include one or more septa 1401 which can be used toprime the dome 1410 and/or the various fluid channels of the flusherwith a fluid such as saline, or to inject drugs or therapeutic agentsfor delivery to the patient. In use, the septum 1401 can be pierced witha needle and fluid can be injected through the septum and into theflusher 1400, e.g., to clear any air bubbles from the interior of theflusher. Each septum 1401 can be formed from a self-sealing materialsuch as silicone such that the septum reseals itself after the needle iswithdrawn. The flusher 1400 can be primed before or after implantationin the patient. In some embodiments, the dome 1410 itself can act as aself-sealing septum which can be pierced with a needle to prime theflusher 1400. Each septum 1401 can be mounted sub-flush in a bore holeconfigured to receive a plug 1403 to provide a seal over the septum. Theplug 1403 can be configured to couple to the flusher body (e.g., via asnap fit, interference fit, threaded fit, or the like) after the flusher1400 is primed via the septum 1401. Septa can be included to providefluid paths into any of the channels or chambers of the flusher 1400.

In use, the flusher 1400 generally has two operating modes. In a normaloperating mode, the bypass valve 1430 is open and fluid is allowed toflow freely from the upstream port 1406 to the downstream port 1408.When the flusher 1400 is implanted in a patient as part of a shuntsystem, fluid is free to flow from the ventricle and through the flusherto a valve or drain catheter disposed downstream from the flusher. Inthe normal operating mode, the dome 1410 remains filled with fluidpreviously supplied to the dome through the refill channel 1418.

In a flush operating mode, a force is exerted on the dome 1410 tocollapse the dome and displace fluid therefrom into the flush channel1416. This causes the differential pressure across the flush valve 1424to increase until the popping pressure of the valve is reached, at whichpoint the valve opens and the pressurized fluid is suddenly released.The sudden release results in an upstream “cough” or flush of fluid backthrough the ventricle channel 1412, which can be effective to clearobstructions from a ventricle catheter or other upstream component ofthe shunt system, or to open auxiliary flow paths as described furtherbelow. The cough of fluid causes the bypass valve 1430 to close,preventing the cough from travelling to the downstream port 1408. Therefill valve 1428 also remains closed when the dome 1410 is actuated,preventing fluid from escaping through the refill channel 1418. Afterthe cough of fluid is released, the low-pressure drainage flow throughthe bypass channel 1420 resumes and the ball 1432 naturally floats awayfrom the seat 1434. The ball 1432 can also be actively urged away fromthe seat 1434 by a spring or other biasing mechanism. The flush valve1424 closes once the pressure subsides, and the refill valve 1428 opensto allow the dome 1410 to be refilled through the refill channel 1418.

In some embodiments, the refill valve 1428 orifice can be larger incross-sectional area than the drain channel 1414, such that fluidpreferentially flows through the refill valve to refill the dome 1410before flowing through the drain channel to downstream components of theshunt system 100. The dome 1410 can have ribs or resilient materialproperties such that the dome is self-righting. As the dome 1410 returnsto its un-collapsed configuration, it can provide a suction force todraw fluid into the dome, allowing the dome to be preferentiallyrefilled.

The size of the refill channel 1418 can be selected to control the rateat which the dome 1410 is refilled. For example, the cross-sectionalarea of the refill channel 1418 can be made small to choke the flow offluid into the dome 1410. In embodiments in which the dome 1410 hasresilient properties, this can advantageously prevent the dome fromquickly springing back to the non-collapsed configuration and generatinga reflux action in which debris or obstructions cleared by a flushingoperation are sucked back into the shunt system.

The flusher 1400 thus facilitates generation and application of a highpressure cough of fluid which flushes the ventricle side of the shuntsystem only. The bypass valve 1430 prevents the cough of fluid fromtravelling through the drain side of the shunt system.

The illustrated flusher 1400 is packaged in a compact form factor thatis amenable to implantation beneath the scalp of a patient. In anexemplary embodiment, the flusher 1400 can be about 1.0 inches long,about 0.25 inches wide, and about 0.25 inches tall.

FIGS. 14D-14G illustrate a flusher 1400′ having a plurality of modularcomponents which can be coupled to one another, for example using boltsor screws. The modular nature of the flusher 1400′ can advantageouslyallow for easy customization of the device, for example by combiningdifferent valve modules with different dome modules and/or differentchannel modules. The valve modules can be selected from a group of valvemodules having different valve sizes, shapes, opening pressures, etc.The dome module can be selected from a group of dome modules havingdifferent volumes, material properties, etc. The channel module can beselected from a group of channel modules having different diameters,relative lengths, etc.

In the illustrated embodiment, the flusher 1400′ includes an upstreamport module 1405′, a flush valve module 1407′, a channel module 1409′, adome module 1411′, a refill valve module 1413′, and a downstream portmodule 1415′. Except as indicated and as will be apparent to one ofordinary skill, the structure and function of the flusher 1400′ issubstantially identical to that of the flusher 1400. The upstream portmodule 1405′ includes the upstream port 1406′. The flush valve module1407′ includes the flush valve 1424′ and the bypass valve 1430′. Thechannel module 1409′ includes the flush channel 1416′, the refillchannel 1418′, and a portion of the bypass channel 1420′. The domemodule 1411′ includes the dome 1410′. The refill valve module 1413′includes the refill valve 1428′. The downstream port module 1415′includes the downstream port 1408′. First and second coupling screws orbolts 1417′ extend longitudinally through the various modules of theflusher, coupling the modules to one another. The dome module 1411′ iscoupled to the channel module 1409′ by a plurality of screws or bolts1419′.

The valves 1202, 1346, and 1430 disclosed above can be usedinterchangeably in any of the flushers 1200, 1300, 1400, 1400′. Inaddition, other valve types can be used, such as the diaphragm valve1500 shown in FIGS. 15A-15C. For example, the diaphragm valve 1500 canbe used in place of the bypass valve 1430 of the flusher 1400 and/or inplace of the flapper valve 1346 of the flush system 1300. The diaphragmvalve 1500 includes a flat elastomeric disc 1502 with one or moreopenings 1504 formed therethrough. The disc 1502 is positioned in afirst fluid lumen 1506 adjacent to a port 1508 of a second lumen 1510that is to be opened and closed by the diaphragm valve 1500, e.g., witha small separation distance D between the disc 1502 and the mouth of theport 1508. In operation, when low pressure flow in the direction of thearrow A3 exists in the fluid lumen 1506, the disc 1502 remains in aplanar configuration as shown in FIG. 15B and fluid flows through theopenings 1504 of the disc, such that the first lumen 1506 is in fluidcommunication with the second lumen 1510. When the differential pressureacross the disc 1502 increases (e.g., when a flushing cough is emittedin the first lumen 1506), the disc deforms to a convex configuration asshown in FIG. 15C and a center portion 1512 of the disc presses againstthe port 1508 to seal off the port. The openings 1504 in the disc 1502are formed in the periphery of the disc, outside of the center portion1512, such that fluid communication between the first lumen 1506 and thesecond lumen 1510 is cut off when the disc is deformed into the convexconfiguration. When the pressure differential subsides, resilientproperties of the disc 1502 cause it to regain its planar configuration,restoring fluid communication between the first lumen 1506 and thesecond lumen 1510.

Other valves which can be used with the flushers 1200, 1300, 1400, 1400′include Belleville type valves 1500′ of the type shown in FIGS. 15D-15E,available from MINIVALVE, INC. of Cleveland, Ohio. Specifically, thevalve 1500′ can be positioned such that the dome of the flusher is influid communication with the valve inlet 1502′. When a flush operationis performed, pressure generated in the dome lifts the valve body 1508′off of its seat, forming a fluid path between the valve inlet 1502′ andthe valve outlet 1504′ as shown by the arrows in FIG. 15E. In the openposition, a flush of fluid can flow from the dome, through the valve1500′, and out of the ventricle catheter. The sides 1506′ of the valvechamber can be open to form part of the valve outlet 1504′, or can beclosed such that the valve outlet 1504′ is only at the top of the valvechamber.

In some embodiments, the flushers disclosed herein can be configured togenerate a flushing cough of fluid at a pressure of between about 20psig to about 40 psig or more. In some embodiments, the volume of theflush can be between about 0 mL and about 1 mL or more. It will beappreciated that the flushers 1200, 1300, 1400, 1400′ disclosed aboveare merely exemplary, and that any of a variety of flushers can be usedwith a shunt system in accordance with the teachings herein. A varietyof exemplary flusher embodiments are disclosed in the description thatfollows. Except as indicated below or as will be readily appreciated byone having ordinary skill in the art given the context, the structureand operation of these various embodiments is similar or identical tothat of the embodiments described above. Accordingly, a detaileddescription of such structure and operation is omitted here for the sakeof brevity.

FIG. 16 illustrates another exemplary embodiment of a flusher 1600. Thedome 1602 of the flusher includes a stem 1604 that extends from aninterior ceiling of the dome and that pinches off or occludes the bypasschannel 1606 when the dome is actuated, cutting off fluid flowtherethrough and eliminating the need for a dedicated bypass valve inthe bypass channel. The flusher 1600 includes an umbrella valve 1608configured to crack open to release a flush of fluid in the upstreamdirection when the differential pressure across the valve exceeds athreshold amount. The refill channel 1610 for the flusher dome can bedisposed directly beneath the stem 1604 such that it too is blocked whenthe dome 1602 is depressed.

FIG. 17 illustrates another exemplary embodiment of a flusher 1700. Theflusher 1700 includes a flapper valve 1702 having a stem 1704 and a bulbportion 1706. The flapper valve 1702 is configured to pivot in thedirection of the arrow A4 about a hinge axis 1708 (e.g., a pivot pin towhich the stem 1704 is coupled or a living hinge formed in the stem)when the flusher dome 1710 is depressed to perform a flushing operation.The flapper valve 1702 pivots until the bulb 1706 contacts a ramp orwedge portion 1712 of the flusher body 1714, sealing off the drain side1716 of the shunt system until the flushing operation is completed. Theflapper valve 1702 can be biased towards the open configuration in whichthe drain port 1716 is in fluid communication with the ventricle port1718. A small refill orifice 1720 is provided to refill the dome 1710when flow through the flusher resumes, and can be sized to restrict therate at which the dome returns to its un-collapsed configuration.

FIG. 18 illustrates another exemplary embodiment of a flusher 1800. Theflusher 1800 includes a piston and spring valve 1802 configured to movein the direction of the arrow A5 when the flush dome 1804 is depressed.The piston 1806 moves until it hits a stop 1808, which maintains thepiston in a position that occludes a passageway 1810 between theventricle port 1812 and the drain port 1814. Accordingly, the flushreleased through the piston and spring valve 1802 flows only to theventricle port and not to the drain port. A small refill lumen 1816 isformed through the center of the piston 1806 such that, when theflushing operation is completed and the piston returns under the bias ofthe spring 1818 to its original position, fluid can flow through therefill lumen to refill the dome 1804.

FIGS. 19A-19B illustrate another exemplary embodiment of a flusher 1900.The flusher 1900 includes a piston and spring valve 1902 disposed in aflush lumen 1904 that extends between a ventricle lumen 1906, a drainlumen 1908, and a dome 1910. The piston 1912 is biased to a firstposition, shown in FIG. 19A, in which it is not disposed between theventricle and drain lumens 1906, 1908 and in which fluid is free to flowfrom the ventricle lumen to the drain lumen. The piston 1912 also has asecond position, shown in FIG. 19B, to which the piston is moved whenthe dome 1910 is actuated. In the second position, the piston 1912 isdisposed between the ventricle and drain lumens 1906, 1908 and therebycuts off fluid communication between the ventricle and drain lumens suchthat the flushing cough only flows to the ventricle lumen. The piston1912 can include a refill lumen as described above with respect to theflusher 1800 of FIG. 18.

FIGS. 20A-20B illustrate another exemplary embodiment of a flusher 2000.The flusher 2000 includes a flapper valve 2002 actuated by a mechanicallever/linkage system 2004 to block the drain side of the system when aflushing operation is performed. The lever 2004 has a first arm 2006disposed under the flush dome 2008 which pivots in a clockwise directionwhen the flush dome is depressed into contact with the first arm. Thispivoting movement of the first arm 2006 causes longitudinal translationof a center link 2010 of the linkage, which in turn causes pivotingmovement of a flapper 2012. As shown in FIG. 20A, during normaloperation, the flapper 2012 seals the flush lumen 2014 and fluid is freeto flow from the ventricle port 2016 to the drain port 2018. As shown inFIG. 20B, when a flushing operation is performed, the lever 2004 isactuated to move the flapper 2012 such that the drain port 2018 issealed and a flush generated in the dome 2008 flows only through theventricle port 2016. When the flush is completed, the lever 2004 returnsto its original position, either naturally or under the bias of a springor other biasing mechanism. A small refill port (not shown) can beformed in or around the flapper 2012 to allow the dome 2008 to berefilled after a flushing operation is completed and/or to limit therate at which the dome is refilled.

FIGS. 21A-21B illustrate another exemplary embodiment of a flusher 2100.The flusher 2100 includes a flush valve 2102 formed by a pair ofelastomeric lips 2104. While two lips 2104 are shown, it will beappreciated that any number of lips can be provided. Each lip isattached at one end to the sidewall of the flush lumen 2106. The otherend of the lip is free to move towards or away from the dome 2108 inresponse to fluid pressure exerted thereon. As shown in FIG. 21A, duringnormal operation, the lips 2104 are directed inwardly towards theflushing dome 2108 and fluid is free to flow from the ventricle port2110 to the drain port 2112. As shown in FIG. 21B, when a flushingoperation is performed, the lips 2104 are urged outwardly away from thedome 2108 under the force of the flushing cough of fluid. The lips 2104are sized and configured such that, when disposed as shown in FIG. 21B,the drain port 2112 is sealed by one of the lips while the ventricleport 2110 is placed in fluid communication with the dome 2108, such thata flush generated in the dome flows only through the ventricle port. Arecess 2114 can be formed in the ventricle port 2110 to allow fluid toflow around the upstream lip when the lips are positioned as shown inFIG. 21B. When the flush is completed, the lips 2104 return to theiroriginal position, either naturally or under the bias of a spring orother biasing mechanism. A small refill port (not shown) can be formedin the lips 2104 to allow the dome 2108 to be refilled after a flushingoperation is completed and/or to limit the rate at which the dome isrefilled.

FIG. 22 illustrates another exemplary embodiment of a flusher 2200. Theflusher 2200 includes a flexible or compliant drain lumen 2202 which canbe compressed by an external force (e.g., finger pressure applied to theflusher through the patient's skin) to occlude the drain port. In use,the drain lumen 2202 is compressed to occlude the drain port while aflushing operation is performed, such that the flush is directed onlythrough the ventricle port 2204. In other words, the drain lumen 2202can be compressed to cut off fluid communication between the drain lumenand the ventricle port 2204 and between the drain lumen and the flushinglumen 2206. In some embodiments, the drain lumen 2202 can includeinternal protrusions or a section having a reduced cross-sectional area2208 to more-reliably occlude the drain lumen when external pressure isapplied thereto. The drain lumen 2202 can also include external featuresto facilitate location of the drain lumen through the skin. For example,a push-button, protrusion, dome, or other external feature can beprovided to provide tactile feedback to a user.

FIG. 23 illustrates another exemplary embodiment of a flusher 2300. Theflusher 2300 includes a collapsible stem 2302 that extends from theinterior ceiling of the dome 2304 to the base 2306 of the flusher body.The illustrated stem includes upper and lower portions that engage oneanother with opposed saw tooth bearing surfaces 2308. The surfaces 2308are configured such that a predetermined threshold force applied to thestem 2302 in the longitudinal direction is required to deflect the teethenough for the stem to collapse and allow the dome 2304 to becompressed. Accordingly, the dome 2304 can only be depressed when apredetermined threshold force is applied, which can prevent inadvertentflushing or compression of the dome. The stem 2302 can also beconfigured to emit or provide tactile feedback, e.g., in the form of aclick or snap, to provide confirmation to the user that sufficient forcewas applied to initiate a flushing operation.

FIG. 24 illustrates another exemplary embodiment of a flusher 2400. Theflusher 2400 includes a ball and spring valve 2402 with first and secondO-rings 2404 that act as valve seats for the ball and spring valve. Theball 2406 is biased by the spring 2408 to a first position, shown inFIG. 24A, in which the ball is seated against the upper O-ring to cutoff fluid communication between the dome 2410 and the ventricle anddrain ports 2412, 2414. In this position, fluid is free to flow from theventricle port 2412 to the drain port 2414. When a flushing operation isperformed, the ball 2406 moves to a second position in which the ball isseated against the lower O-ring to cut off fluid communication betweenthe drain port 2414 and the dome 2410 and between the drain port and theventricle port 2412. Accordingly, the flushing cough only flows to theventricle port 2412. The dimensions of the ball 2406 and the strength ofthe spring 2408 can be selected to control the opening pressure of theball and spring valve, e.g., to ensure the valve only opens when ahigh-pressure cough is generated in the dome 2410. A refill lumen (notshown) can be formed between the ventricle port 2412 and the dome 2410(e.g., through the ball) to allow the dome to be refilled after aflushing operation is performed.

FIGS. 25A and 25B illustrate another exemplary embodiment of a flusher2500. The flusher 2500 includes an L-shaped piston valve 2502 havingfirst and second legs 2504, 2506. During normal operation, the piston2502 is biased by a spring 2508 to the position shown in FIG. 25A, suchthat a fluid lumen 2510 formed through the first leg 2504 of the piston2502 provides fluid communication between the ventricle port 2512 andthe drain port 2514 and such that the body of the piston blocks fluidcommunication between the dome 2516 and the ventricle and drain ports.When a flushing operation is performed, the force of the flush urges thepiston 2502 down against the force of the bias spring 2508, such thatboth ends of the fluid lumen 2510 are occluded. In addition, a secondleg 2506 of the piston 2502 is positioned such that it occludes thedrain port 2514. The piston 2502 is displaced such that the ventricleport 2512 is not occluded, and therefore the ventricle port is placed influid communication with the flush dome 2516 as shown in FIG. 25B suchthat the flushing cough flows only through the ventricle port.

In any of the embodiments disclosed herein, the dome can include one ormore features for biasing the dome towards a collapsed configuration ortowards an un-collapsed configuration. For example, a coil spring 2602(shown in FIG. 26A) or a leaf spring 2604 (shown in FIG. 26B) can bedisposed within the dome and can extend from an interior ceiling of thedome to a base of the flusher body. In some embodiments, the spring canbe biased to urge the dome towards a collapsed configuration, such thatthe spring controls the rate at which the dome expands when refill fluidis supplied thereto. In other embodiments, the spring can be biased tourge the dome towards an un-collapsed position, such that the springhelps return the dome to a starting position after a flushing operationis performed.

FIG. 27 illustrates another exemplary embodiment of a flusher 2700. Theflusher 2700 includes a stem 2702 that extends from an interior ceilingof the dome and includes a tongue 2704 with a fluid lumen 2706 formedtherethrough. During normal operation, the dome 2708 is in anun-collapsed configuration and the tongue 2704 is positioned as shown inFIG. 27 such that the fluid lumen 2706 formed therein provides fluidcommunication between the ventricle port 2710 and the drain port 2712.In this position, the tongue 2704 blocks fluid communication between thedome 2708 and the ventricle and drain ports 2710, 2712. When a flushingoperation is performed, the dome 2708 is depressed or collapsed and thetongue 2704 is shifted down, such that the fluid lumen 2706 extendingthrough the tongue is moved out of alignment with the ventricle anddrain ports 2710, 2712 and the tongue occludes the drain port. A cut-outor flow channel 2714 is formed in the tongue 2704 such that when thetongue is shifted down to block the drain port 2712, the ventricle port2710 is placed in fluid communication with the dome 2708 and theflushing cough flows only through the ventricle port. When the flushingoperation is completed, a portion of the fluid flowing from theventricle port 2710 to the drain port 2712 refills the dome 2708 througha refill capillary 2716, which can be sized to limit the rate at whichthe dome returns to its un-collapsed configuration.

FIGS. 49A-49G illustrate an exemplary embodiment of a flusher 4900. Theflusher 4900 generally includes an outer shell or body 4902 that definesa flush dome 4904. The bottom surface of the body 4902 can be closed bya base plate 4906 to which the body is sealed. A flush valve assembly4908 and a refill valve assembly 4910 can be disposed within the body4902, and a pinch tube 4912 can extend over the top of the flush dome4904.

The flush valve assembly 4908 includes a valve cartridge 4914, a valvebody 4916, and an adjustment disc 4918. The valve cartridge 4914includes an upstream port 4920 configured to be coupled to or placed influid communication with a ventricular catheter, a flush port 4922configured to be placed in fluid communication with the flush dome 4904,and a passive flow port 4924 configured to be placed in fluidcommunication with a passive flow lumen 4926 defined by the body 4902.Each of the ports 4922, 4924, 4926 are in fluid communication with aninterior chamber defined 4928 by the valve cartridge 4914. The upstreamport 4920 and/or the flush port 4922 can be defined by male barbedfittings that extend radially outward from the valve cartridge 4914. Thebarbed fittings can advantageously facilitate coupling of the flushvalve assembly 4908 with the body 4902 (in the case of the flush port4922) or with a ventricular catheter or other shunt system component (inthe case of the upstream port 4920). The passive flow port 4926 can bedefined by an opening formed in a sidewall of the valve cartridge 4914.The valve cartridge 4914 and the barbed fittings can be formed asmonolithic, one-piece component which can advantageously provide a highstrength unit capable of withstanding high operating pressures andlateral stress on the upstream port fitting 4920. High interferencebarbed fittings can be used to allow high pressure operation withoutleakage, which allows the flushing pressure to be delivered only to theflush valve and facilitates more precise and repeatable opening pressurethresholds. In some embodiments, the barbed fittings can be configuredto withstand up to 120 psi.

The valve body 4916 can be an umbrella-type valve, a Belleville-typevalve, or the like. The valve body 4916 is sandwiched between the upperwall of the chamber 4928 and the adjustment disc 4918 in an interferencefit such that the valve body is compressed. The valve body 4916 definesa substantially concave upper surface that forms a fluid-tight seal withthe upper wall of the chamber 4928 to seal off the flush port 4922 fromthe upstream port 4920 and the passive flow port 4924 during normaloperation. When sufficient pressure is applied to the upper surface ofthe valve body 4916, the valve body deforms away from the upper wall ofthe chamber 4928 to allow fluid communication between the flush port4922 and the upstream port 4920 and between the flush port and thepassive flow port 4924. The threshold pressure at which the valve body4916 opens can be infinitely adjusted by adjusting the pressure exertedon the valve body by the adjustment disc 4918. In the illustratedembodiment, the adjustment disc 4918 is threadably mounted in thecartridge 4914 such that rotating the disc in a first directionincreases the compression of the valve body 4916 to increase thethreshold pressure, and such that rotating the disc in a second,opposite direction decreases the compression of the valve body todecrease the threshold pressure. It will be appreciated that other meansof adjusting the compression of the valve body 4916 can be used insteador in addition. A driving interface 4930 can be formed in the bottomsurface of the adjustment disc 4918 to facilitate rotation of the discby a driving tool. In the illustrated embodiment, the driving interface4930 comprises first and second opposed cylindrical recesses configuredto receive corresponding first and second pins of a driving tool. Thearrangement of the recesses can allow rotation of the disc 4918 to beeasily visualized and to be performed in a repeatable and controlledmanner. The adjustment disc 4918 can be adjusted in-process and lockedin a desired position using an adhesive (e.g., medical gradecyanoacrylate or the like). Locking the disc 4918 in place, e.g., byfreezing the threads using an adhesive, can advantageously allow for thethreshold pressure of the valve to be securely maintained at the desiredlevel.

When the valve body 4916 is sealed against the upper wall of the chamber4928, fluid can flow from the upstream port 4920, into the chamber,around the outside of the closed valve body, and into the passive flowport 4924.

The flush valve assembly 4908 can be positioned within a cavity 4932defined in the body 4902 of the flusher 4900 such that the upstream port4920 protrudes through a sidewall of the body and such that the flushport 4922 extends into a passage 4934 that connects the cavity to theflush dome 4904. When the flush valve assembly 4908 is disposed in thebody 4902, the passive flow port 4924 is aligned with the passive flowchannel 4926 defined in the body.

The refill valve assembly 4910 includes a refill valve 4936 and a refillplate 4938. The refill plate 4938 is mounted in the body 4902 beneaththe flush dome 4904. A passive flow channel 4940 extends through therefill plate 4938 and is in fluid communication with the passive flowchannel 4926 of the body 4902 at one end and the pinch tube 4912 at theother end. The refill valve 4936 is operable to selectively place thepassive flow channel 4940 in fluid communication with the interior ofthe flush dome 4904, for example to refill the flush dome after aflushing operation is performed. In the illustrated embodiment, therefill valve 4936 is an umbrella valve that includes a valve stem and avalve head. The stem is mounted within a valve guide formed in therefill plate 4938. A plurality of openings 4942 are formed in the plate4938 around the circumference of the valve guide. When the refill valve4936 is closed, the valve head covers the plurality of openings 4942 andprevents fluid communication between the passive flow channel 4940 andthe flush dome 4904. When the refill valve 4936 is opened, the valvehead is lifted off of the openings 4942 such that fluid can flow betweenthe passive flow channel 4940 and the flush dome 4904.

As perhaps best shown in FIG. 49C, the refill valve 4936 is disposedbeneath the flush dome 4904 and oriented such that the axis A1 alongwhich the valve opens and closes is substantially parallel to the axisA2 along which the flush dome is actuated. In other words, when anactuation force is applied to the flush dome 4904 during a flushingoperation, the primary component of the actuation force acts in the samedirection as the valve closing direction. Also, the stacked nature ofthe refill valve 4936 and flush dome 4904 allows pressure in the flushdome to act directly on the refill valve, helping ensure that the refillvalve is closed when the flush dome is actuated. The stacked arrangementalso reduces the overall length and profile of the flusher 4900.

The refill plate 4938 can be rigid, semi-rigid, or flexible. The refillplate 4938 can mechanically interlock with the body 4902 to provide arobust connection capable of withstanding high operating pressures. Asshown, the refill plate 4938 can be disc-shaped and can include asidewall that extends about a circumference of the plate and protrudesradially-outward and axially upward to define a lip 4944 that isreceived within a corresponding annular recess or undercut 4946 formedin the body 4902. The body 4902 can be formed from a flexible materialto allow the body to be stretched over the lip 4944 of the refill plate4938 during assembly. In some embodiments, the body 4902 is molded fromsilicone and bonded to the refill plate 4938 using silicone RTV or otheradhesive. The base plate 4906 can likewise be bonded to the body 4902and/or to the refill plate 4938 using silicone RTV or the like. The baseplate 4906 can be formed from silicone and can include a polyesterreinforcing mesh.

The pinch tube 4912 can be configured to provide a valve-less means ofclosing off the drain side of the shunt system during a flush operation.The pinch tube 4912 extends out of the body 4902, across the top of theflush dome 4904, and into a coupling where it is placed in fluidcommunication with a downstream port 4948 configured to be coupled to orplaced in fluid communication with a drain catheter, shunt valve, orother downstream device (e.g., via a drain tube 4950 as shown). Thepinch tube 4912 can be positioned such that it will naturally becompressed by a user when the user actuates the flush dome 4904. Theflusher 4900 thus allows a single user motion, applied at a singlecontiguous contact area, to both seal off the drain side of the systemand actuate the flush dome. In some embodiments, the pinch tube 4912 canbe more easily deformable than the flush dome 4904 to increase thelikelihood that the pinch tube is closed off when a flushing operationis performed. For example, the pinch tube 4912 can be formed from amaterial having a lower durometer than the material used to form theflush dome 4904. In an exemplary embodiment, the pinch tube 4912 isformed from 30 durometer silicone while the flush dome 4904 is formedfrom 70 durometer silicone.

As shown in FIGS. 49F and 49G, the flusher 4900 employs a substantiallyT-shaped configuration in which the longitudinal axis of the flusherbody 4902 extends perpendicular to the longitudinal axis of the upstreamport 4920 and the longitudinal axis of the drain tube 4950. This canadvantageously allow the flusher 4900 to be used with existing shuntsystems without increasing the distance between the anchor and the shuntvalve. The T-configuration can thus reduce or eliminate the need to addlength to the overall shunt system, and allows the flusher 4900 to bepositioned more proximate to an incision over the burr hole that istypically used when implanting shunt systems.

The flusher 4900 can be operable in a passive flow mode, a flushingmode, and a refill mode.

During the passive flow mode of operation, the flush valve 4916 and therefill valve 4936 are both closed. Fluid from a ventricular catheterflows into the valve cartridge 4914 via the upstream port 4920. Thefluid flows around the closed valve body 4916 and into the passive flowport 4924 of the valve cartridge 4914. From there, the fluid flowsthrough the passive flow channel 4926 of the body 4902 and through thepassive flow channel 4940 of the refill plate 4938, past the closedrefill valve 4936. The fluid then flows through the pinch tube 4912,into the drain tube 4950, and then into a shunt valve, drain catheter,or other downstream component of the shunt system.

A user can initiate a flushing operation by applying pressure to the topof the flush dome 4904 (e.g., by exerting downward finger pressure onthe dome through a patient's skin), to collapse or compress the dome.During the flushing mode of operation, the pinch tube 4912 collapsesunder the pressure being applied by the user to cut off fluidcommunication to the drain tube 4950 and the downstream components ofthe shunt system. As the flush dome 4904 is depressed, the pressure inthe flush dome increases, holding the refill valve 4936 in the closedposition. The pressure in the flush dome 4904 increases until thethreshold pressure of the flush valve 4916 is reached, at which pointthe flush valve opens releasing a cough or burst of fluid into the valvecartridge 4914. The collapsed pinch tube 4912 prevents the burst offluid from flowing through the passive flow channels 4926, 4940, andtherefore the burst of fluid instead flows through the upstream port4920. This upstream “cough” or flush of fluid can be effective to clearobstructions from a ventricle catheter or other upstream component ofthe shunt system, or to open auxiliary flow paths as described furtherbelow. Once the burst of fluid is released, the flush valve 4916 returnsto the closed position.

When a flushing operation is completed and the flush dome 4904 isreleased, the pinch tube 4912 opens to reestablish flow to thedownstream port 4948 and the flush dome gradually returns to its raisedposition. During this refill mode of operation, the flush valve 4916 isclosed. Expansion of the flush dome 4904 causes the pressure in theflush dome to drop below the pressure in the passive flow channel 4940,which creates a pressure differential that causes the refill valve 4936to open. Fluid flowing through the passive flow channel 4940 can thenflow through the openings 4942 formed in the refill plate 4938 to refillthe flush dome 4904. The cross-sectional area of the openings 4942 canbe made relatively small to limit the rate at which the flush dome 4904is refilled and therefore the rate at which the flush dome expands. Thiscan advantageously prevent debris flushed from the shunt system duringthe flushing operation from being sucked back in as the flush dome 4904expands. Once the flush dome 4904 is refilled, the flusher 4900 returnsto the passive flow mode of operation.

The flusher 4900 thus facilitates generation and application of a highpressure cough of fluid which flushes the ventricle side of the shuntsystem only. The pinch tube 4912 prevents the cough of fluid fromtravelling through the drain side of the shunt system. In otherembodiments, however, the flusher 4900 can be configured to flush thedrain side of the system instead or in addition.

FIGS. 50A-50I illustrate another exemplary embodiment of a flusher 5000.The flusher 5000 includes a flush dome 5004 that has a recess 5052formed in an outer surface thereof in which a pinch tube 5012 can bedisposed. The pinch tube is compressed when the flush dome 5004 isdepressed to seal off the drain side of the system and direct the coughof fluid towards the upstream side of the system.

During normal operation, fluid from a ventricular catheter flows intothe flusher 5000 via an upstream port 5020. The fluid flows around aclosed flush valve 5016, into a passive flow channel of the body 5026,and into a pinch tube 5012 disposed in the recess 5052 of the flush dome5004. The fluid then flows into a shunt valve, drain catheter, or otherdownstream component of the shunt system.

A user can initiate a flushing operation by applying pressure to the topof the flush dome 5004 (e.g., by exerting downward finger pressure onthe dome through a patient's skin), to collapse or compress the dome.During the flushing mode of operation, the pinch tube 5012 collapsesunder the pressure being applied by the user to cut off fluidcommunication to the downstream components of the shunt system. As theflush dome 5004 is depressed, the pressure in the flush dome increasesuntil the threshold pressure of the flush valve 5016 is reached, atwhich point the flush valve deforms away from a valve seat 5018, openingthe valve and releasing a cough or burst of fluid through the upstreamport 5020. The cough of fluid flows out of the flush dome 5004, througha flush channel 5022 defined in the body 5002 and between the valve seat5018 and a flush channel cover 5054, and through the flush valve 5016 tothe upstream port 5020. This upstream “cough” or flush of fluid can beeffective to clear obstructions from a ventricle catheter or otherupstream component of the shunt system, or to open auxiliary flow pathsas described further below. Once the burst of fluid is released, theflush valve 5016 returns to the closed position.

When a flushing operation is completed and the flush dome 5004 isreleased, the pinch tube 5012 opens to reestablish flow to thedownstream port 5048 and the flush dome gradually returns to its raisedposition. During this refill mode of operation, the flush valve 5016 isclosed. As the flush dome 5004 expands, it is refilled with fluid fromthe passive flow channel 5026 via a refill port (not shown). Any of avariety of refill port arrangements can be used, as discussed below.Once the flush dome is refilled, the flusher 5000 returns to the passiveflow mode of operation.

FIG. 51 illustrates another exemplary embodiment of a flusher 5100. Theflusher 5100 includes an upstream port 5120 configured to be coupled toor placed in fluid communication with a ventricular catheter and adownstream port 5148 configured to be coupled to or placed in fluidcommunication with a drain catheter or other downstream component of ashunt system. The flusher 5100 includes a flush dome 5104 and a flushvalve 5116. Like the flusher 5000, the flusher 5100 does not include adedicated refill valve. A dual lumen tube 5112 extends over the flushdome 5104 from the downstream port 5148 to the chamber 5128 in which theflush valve 5116 is disposed. A drain lumen 5156 of the tube 5112 isopen to the downstream port 5148 while a refill lumen 5158 of the tubeis closed just downstream of the flush dome 5104 and is in fluidcommunication with an interior of the flush dome via a refill port 5160.During normal operation, fluid flows from the upstream port 5120, aroundthe flush valve 5116, through the drain lumen 5156 of the tube 5112 andout the downstream port 5148. The fluid also flows through the refilllumen 5158 of the tube 5112 to refill the flush dome 5104 if necessary.When the flush dome 5104 is actuated by a user, the drain and refilllumens 5156, 5158 are pinched off and pressure builds in the flush domeand a flush channel 5122 until the threshold pressure of the flush valve5116 is reached, causing the flush valve to open and release a cough offluid through the upstream port 5120.

FIG. 52 illustrates another exemplary embodiment of a flusher 5200. Theflusher 5200 is substantially identical to the flusher 5100, except thatthe connection 5260 between the refill lumen 5258 and the flush dome5204 is disposed at the apex of the flush dome (e.g., at the center ofthe upper wall of the flush dome). This can advantageously make it morelikely that the refill port 5260 is blocked when the flush dome 5204 isbeing depressed by a user.

FIG. 53 illustrates another exemplary embodiment of a flusher 5300. Theflusher 5300 is substantially identical to the flusher 5100, except thatthe dual lumen tube is replaced with a single lumen tube 5312 that actsboth as a drain lumen and as a refill lumen.

FIG. 54 illustrates another exemplary embodiment of a flusher 5400. Theflusher 5400 is substantially identical to the flusher 5300, except thatthe refill connection 5460 between the tube 5412 and the flush dome 5404extends at an oblique angle relative to the central longitudinal axis ofthe tube. This can advantageously make it more likely that the refillport 5460 is blocked when the flush dome 5404 is depressed by a user,since a force applied away from the center of the flush dome will moreeasily result in the connection being sealed off.

FIG. 55 illustrates another exemplary embodiment of a flusher 5500. Theflusher 5500 is substantially identical to the flusher 5100, except thatthe dual lumen tube is replaced with a single lumen tube 5556 having aninner tube 5558 nested therein.

It will be appreciated that various other arrangements can be employedto provide a refill lumen and a drain lumen that are closed off when theflush dome is actuated by a single user motion. For example, as shown inFIG. 56A, the refill lumen 5658 can be coiled around the drain lumen5656 and the refill and drain lumens can extend over the top of theflush dome 5604 where a user is likely to apply pressure when actuatingthe dome. As shown in FIG. 56B, the refill lumen 5658 can cross over thedrain lumen 5656 at a position that lies over the center of the flushdome 5604 where a user is likely to apply pressure when actuating thedome. As shown in FIG. 56C, the drain lumen 5656 can be stacked on topof the refill lumen 5658 and the refill and drain lumens can extend overthe top of the flush dome 5604 where a user is likely to apply pressurewhen actuating the dome. As shown in FIG. 56D, the refill lumen 5658 canbe stacked on top of the drain lumen 5656 and the refill and drainlumens can extend over the top of the flush dome 5604 where a user islikely to apply pressure when actuating the dome. As shown in FIG. 56E,the drain and refill lumens 5656, 5658 can extend side-by-side in aparallel relationship over the top of the flush dome 5604 where a useris likely to apply pressure when actuating the dome.

As shown in FIG. 56F, any of a variety of sectional profiles can be usedin the refill/drain tube of a flusher. The illustrated profiles are: 1)vertically-stacked circular cross section lumens of equal size; 2)horizontally-stacked circular cross section lumens of equal size; 3)horizontally-stacked circular cross section lumens of unequal size; 4)vertically stacked lumens having semi-circular cross sections; 5) afirst lumen having a circular cross section and a second lumen having acrescent cross section, the circular lumen having a greater area thanthe crescent lumen; 6) a first lumen having a circular cross section anda second lumen having a crescent cross section, the crescent lumenhaving a greater area than the circular lumen, the overall cross-sectionof the tube being circular; 7) a first lumen having a circular crosssection and a second lumen having a crescent cross section, the crescentlumen having a greater area than the circular lumen, the overallcross-section of the tube being non-circular; 8) a first lumen having acircular cross section and a second lumen having a crescent crosssection, the circular lumen having a greater area than the crescentlumen, the overall cross-section of the tube being non-circular; 9)first and second lumens having circular cross sections, the overallcross-section of the tube being non-circular; 10) first and secondlumens having circular cross sections, the overall cross-section of thetube being elliptical; 11) first and second lumens having ellipticalcross sections, the overall cross-section of the tube being circular;and 12) first and second coaxial lumens each having a circular crosssection.

The first and second lumens can be coextruded or can be formed from twoseparate components joined together to form a composite tube. FIG. 56Gillustrates a larger crescent shaped tube to which a circular tube iscoupled to form a composite tube having a circular overallcross-section. FIG. 56H illustrates a larger crescent shaped tube towhich a circular tube is coupled to form a composite tube having anon-circular overall cross-section.

The extrusion cross-section can be selected to control whether therefill and drain functions are closed off simultaneously orsequentially. When the refill and drain functions are to be closed offsequentially, the lumen assigned to the refill function and the lumenassigned to the drain function can be selected to control which functionis closed off first when the tube is compressed. For example, in theextrusion profile enumerated above as number 6, the crescent-shapedlumen will close off before the circular-shaped lumen does.

FIG. 57 illustrates another exemplary embodiment of a flusher 5700. Theflusher 5700 includes an upstream port 5720 configured to be coupled toor placed in fluid communication with a ventricular catheter and adownstream port 5748 configured to be coupled to or placed in fluidcommunication with a drain catheter or other downstream component of ashunt system. The flusher 5700 includes a flush dome 5704 and a flushvalve 5716. A ring 5762 is disposed within the flush dome 5704 above thedrain lumen 5756. During normal operation, fluid flows from the upstreamport 5720, around the flush valve 5716, through the drain lumen 5756 andout the downstream port 5748. The fluid also flows through openings 5764in the drain lumen 5756 to refill the flush dome 5704 if necessary. Whenthe flush dome 5704 is actuated by a user, the ring 5762 pinches down onthe drain lumen 5756 to close off the drain side of the system. Fluidflows through an opening 5766 formed in the ring 5762 against the flushvalve 5716 and pressure builds until the threshold pressure of the flushvalve is reached, causing the flush valve to open and release a cough offluid through the upstream port 5720.

It will be appreciated that, in any of the flusher embodiments above,the pinch tube or lumen can be disposed below the flush dome instead ofon top of the flush dome as shown.

In any of the flushers disclosed herein, the flush dome can be sized tocontrol the volume of fluid flushed through the shunt system during aflushing operation. In an exemplary embodiment, the flush dome has aninterior volume of about 1 mL. In any of the flushers disclosed herein,the flush dome can be configured to rebound or return to itsun-collapsed configuration at a slow rate to prevent reflux action fromsucking debris back into the shunt system. For example, the dome can beformed from a material having low resiliency properties such aspolymeric compositions, silicone, nitrile, polyurethane, and so forth.Alternatively, or in addition, the dome can include ribs or otherinternal or external features for controlling the rebound rate of thedome. For example, the dome can include one or more ribs that extendfrom the base of the dome to the center peak of the dome. The ribs canextend along the interior surface of the dome. Alternatively, or inaddition, the thickness of the dome can vary between the base and thepeak. For example, the dome can be thicker at the base than at the peak.While flushers configured to flush only the upstream or ventricular sideof the shunt system are disclosed herein, it will be appreciated thatthe disclosed flushers can be readily modified to flush only thedownstream or drain side of the shunt system and/or to flush both sidesof the shunt system.

Auxiliary Flow Features

In the flusher embodiments disclosed herein, a cough or flush of fluidis directed into components of a shunt system disposed upstream from theflusher (e.g., into a ventricular catheter) to clear obstructions fromthe catheter or to open alternative flow paths through the catheter. Avariety of components (e.g., catheters, switches, etc.) are disclosed inthe description that follows, any of which can be used with any of theflushers disclosed above in accordance with the teachings herein. Inaddition, the components disclosed in the description that follows canbe used with other flushers or, in some instances, without a flusher.Further still, the components disclosed in the description that followscan be used in the upstream or ventricular side of the shunt systemand/or in the downstream or drain side of the shunt system. Any of thefeatures of the catheters 102, 202 disclosed above can be included inany of the catheters disclosed below.

FIGS. 28A-28C illustrate an exemplary embodiment of a catheter 2800. Thecatheter 2800 includes a plurality of inlet holes formed at a distal tipend of the catheter configured to be disposed within a patient'sventricle. While a single-lumen, single-tip catheter is shown, it willbe appreciated that the catheter can be a multi-lumen catheter and/or amulti-tip catheter. For example, the catheter can be a dual lumencatheter with two independent lumens that extend the full length of thecatheter. By way of further example, the catheter can be a split-tipcatheter having first and second tips at the distal end that merge intoa single lumen that extends through the remainder of the catheter.

The plurality of inlet holes includes one or more primary holes 2802which form pathways through which fluid external to the catheter 2800can enter an inner lumen of the catheter. The plurality of inlet holesalso includes one or more auxiliary holes 2804 which are initiallyblocked such that fluid external to the catheter 2800 cannot passthrough the auxiliary holes into an inner lumen of the catheter. Rather,fluid can only pass through the auxiliary holes 2804 after they areforced open (e.g., by a flushing operation of one of the flushersdisclosed above). The auxiliary holes 2804 are initially blocked by amembrane 2806. In some embodiments, the membrane 2806 can be disposedover the exterior surface of the catheter 2800. The membrane 2806 can beformed from a variety of implantable and biocompatible materials, suchas silicone. The membrane 2806 can be stretched across the openings 2804and attached to the catheter 2800 under tension, such that penetrationof the membrane results in a tear in which opposed sides of the tearmove out of the way of the underlying hole. The membrane 2806 can bestretched over the auxiliary holes 2804 in a variety of directions ororientations, which can allow for the tear produced when the membrane isruptured to have some directionality (i.e., to define an opening thatfaces in a particular direction). The stretched membrane 2806 can beattached to the catheter 2800 in various ways. For example, the membrane2806 can be thermally welded to the catheter 2800 using a heat punch,mechanically coupled to the catheter using O-rings disposed around themembrane and the catheter, or molded into or onto the catheter. In someembodiments, a plurality of auxiliary holes can be provided, each havinga membrane stretched in a different direction. The thickness of themembrane, the degree of tension applied to the membrane, and thematerial from which the membrane is formed can be selected to controlthe force required to tear the membrane. In some embodiments, themembrane is formed from silicone and has a thickness of about 0.001inches.

In use, the catheter 2800 is implanted in a patient with the distal tipof the catheter disposed in the patient's ventricle. Fluid enters theprimary holes 2802 of the catheter and flows through the inner lumen ofthe catheter to a downstream portion of the shunt system (e.g., aflusher, a valve, and/or a drain catheter). When the primary holes 2802become clogged or obstructed, or at any other time a user so desires, aflusher can be actuated to deliver a pressurized cough of fluid throughthe inner lumen of the catheter. The cough of fluid can dislodgeobstructions 2808 from the clogged primary holes 2802 and/or cause themembrane 2806 covering one or more auxiliary holes 2804 to burst. Inother words, flushing the catheter can open the auxiliary inlet ports2804 to provide a secondary fluid pathway into the catheter, e.g., whenthe primary fluid pathway becomes clogged or obstructed.

The inset of FIG. 28A shows an auxiliary hole 2804 after the membrane2806 disposed over the hole has been ruptured. FIG. 28B shows a membrane2806 disposed over the catheter without stretching after being rupturedand FIG. 28C shows a membrane 2806′ disposed over the catheter withstretching after being ruptured. As shown, the stretched membraneprovides a larger opening after rupture, since the torn away portion ofthe pre-tensioned membrane is pulled away from the auxiliary hole 2804′.

FIG. 29 illustrates another exemplary embodiment of a catheter 2900. Thecatheter 2900 includes a primary tip 2902 with one or more inlet holes2904 through which fluid can pass to enter the inner lumen of theprimary tip. The catheter 2900 also includes an auxiliary tip 2906 witha cylindrical plug 2908 mounted therein. The plug 2908 includes one ormore auxiliary holes 2910 covered by a membrane 2912 of the typedisclosed above which can be ruptured (e.g., by a flushing cough) toopen the auxiliary holes. The plug 2908 can be formed from a rigidmaterial. In some embodiments the plug 2908 can be about 3-5 mm indiameter.

FIG. 30 illustrates another exemplary embodiment of a catheter 3000. Thesidewall 3002 of the catheter has a fluid lumen 3004 formed therein,such that fluid can flow through the interior lumen 3006 of the catheterand through the sidewall of the catheter. When a flusher downstream fromthe catheter 3000 is actuated, the flushing fluid causes the sidewalllumen 3004 to expand, stretching a bulb-shaped terminal distal end 3008of the catheter like a balloon. As the bulb 3008 is stretched, one ormore inlet holes 3010 formed therein are enlarged, which can free anydebris that is lodged in the inlet holes. In other words, the flushingoperation is effective to stretch open pores 3010 formed in the catheter3000 to clear obstructions.

FIG. 31 illustrates an exemplary embodiment of a catheter bypass switch3100. The bypass switch 3100 can be incorporated into a flusher or intothe ventricular catheter itself. The switch 3100 includes a flushchannel 3102 which can be coupled to the ventricle port of a flusher.The switch 3100 also includes primary and secondary catheter channels3104, 3106 which can be coupled to respective independent lumens of adual-lumen catheter or to two separate catheters. A ball valve 3108 isdisposed in the switch above a detent or recess 3110 sized to receivethe ball when the ball is forced downward by fluid being flushed throughthe flush channel 3102. In operation, the switch is initially configuredas shown in FIG. 31 such that fluid expelled from the flusher in aflushing operation flows through the primary catheter to clear anyblockages or obstructions. If the flush is unable to clear some or allof the obstructions in the primary catheter, the pressure acting on theball 3108 can increase to a point where the friction between the balland the sidewall of the switch 3100 is overcome and the ball moves downinto the detent 3110. This opens the secondary channel 3106 such thatfluid can then flow from the patient's ventricle, through the secondarycatheter, and into the flusher and the downstream portion of the shuntsystem. The opening into the detent 3110 can spring back around the ball3108 after the ball is forced into the detent, such that the ballremains in the detent (and the secondary channel 3106 remains open)after the flushing force is removed. Because fluid does not flow throughthe secondary catheter until the switch 3100 is actuated, there is areduced tendency for debris to flow into and clog the secondary catheterwhile it is not being used.

FIG. 32 illustrates another exemplary embodiment of a catheter bypassswitch 3200. The bypass switch 3200 can be incorporated into a flusheror into the ventricular catheter itself. The switch 3200 includes aflush channel 3202 which can be coupled to the ventricle port of aflusher. The switch also includes primary and secondary catheterchannels 3204, 3206 which can be coupled to respective independentlumens of a dual-lumen catheter or to two separate catheters. A sealingmembrane 3208 is disposed in the switch 3200 across the secondarycatheter channel 3206 such that the secondary catheter channel isinitially sealed off from the rest of the switch. In operation, theswitch 3200 is initially configured as shown in FIG. 32 such that fluidexpelled from the flusher in a flushing operation flows through theprimary catheter to clear any blockages or obstructions. If the flush isunable to clear some or all of the obstructions in the primary catheter,the pressure acting on the membrane 3208 can increase to a point wherethe membrane bursts. This opens the secondary channel 3206 such thatfluid can then flow from the patient's ventricle, through the secondarycatheter, and into the flusher and the downstream portion of the shuntsystem. The membrane 3208 can be self-sealing and/or resealable, or canbe non-resealable such that the secondary channel 3206 is permanentlyopened, even after the flushing force is removed. Because fluid does notflow through the secondary catheter until the switch 3200 is actuated,there is a reduced tendency for debris to flow into and clog thesecondary catheter while it is not being used.

While the switches 3100, 3200 of FIGS. 31 and 32 are actuated by fluidpressure from a flushing operation, the switches can also be actuatedmechanically. For example, as shown in FIG. 33, a switch 3300 caninclude a push button 3302 to which a force can be applied by a userthrough the patient's skin when a primary catheter 3304 is clogged. Thepush button 3302 can be coupled to a pointed stem configured topenetrate a membrane within the switch when the push button is depressedto open the membrane and allow fluid flow through a secondary catheter3306. Alternatively, the push button can be coupled to a stem or leverconfigured to urge the ball of FIG. 31 into the detent to open thesecondary catheter.

FIG. 34 illustrates another exemplary embodiment of a catheter 3400. Thecatheter 3400 includes a split-tip distal end with a primary tip 3402and a secondary tip 3404. The secondary tip 3404 is initially closed bya sealing membrane 3406 stretched across the interior lumen 3408 of thesecondary tip. In use, the membrane 3406 can be ruptured (e.g., asdescribed in the embodiments above) to open the secondary tip 3404 andallow fluid flow therethrough.

FIGS. 35A-35B illustrate another exemplary embodiment of a catheter3500. The catheter 3500 includes a bulb portion 3502 at its terminaldistal end that has a reduced sidewall thickness as compared with therest of the catheter. One or more inlet ports 3504 are formed in thebulb portion 3502 of the catheter to allow fluid external to thecatheter to flow into the inner lumen of the catheter. When the inletports 3504 are blocked or obstructed, a flushing operation can performedby a flusher disposed downstream from the catheter. The high pressureflush generated by the flusher causes the bulb 3502 to stretch, as shownin FIG. 35B, expanding the inlet ports 3504 and dislodging any debris orobstructions that may be caught in the inlet ports.

FIGS. 36A-36B illustrate another exemplary embodiment of a catheter3600. The catheter 3600 includes one or more longitudinal ribs 3602formed on an exterior surface thereof. In the illustrated embodiment,the catheter 3600 includes four external ribs 3602 spaced 90 degreesapart from one another about the circumference of the catheter. The ribs3602 act as standoffs that hold the catheter 3600 and the inlet ports3604 formed therein away from objects in the vicinity of the catheter(e.g., the wall of the patient's ventricle or other tissue 3606).Accordingly, when the catheter is disposed up against the side of thepatient's ventricle or up against other tissue, a path remains open tothe inlet ports on the side of the catheter facing the tissue.

FIG. 37 illustrates another exemplary embodiment of a catheter 3700. Thecatheter 3700 includes independent primary and secondary lumens 3702,3704. Each lumen includes one or more inlet ports 3706 formed therein.In addition, a stylet 3708 is disposed in the secondary lumen 3704 toblock fluid flow therethrough and through the inlet ports 3706 formedtherein. In use, when the primary lumen 3702 becomes blocked orobstructed, the stylet 3708 can be removed to open up flow through thesecondary lumen 3704. The stylet 3708 can be removed during aminimally-invasive surgical procedure in which a small incision isformed adjacent to the proximal end of the catheter 3700, the stylet ispulled out of the secondary lumen 3704, and the incision is closed. Thecatheter of FIG. 37 thus allows a secondary flow channel to be opened upwith a minimally-invasive procedure, as compared with traditionalventricular catheters which, when clogged, must be completely removedand replaced with a new catheter as part of a comparativelymore-invasive procedure.

FIG. 38 illustrates another exemplary embodiment of catheter 3800. Thecatheter 3800 includes a sheath 3802 disposed within the inner lumen3804 of the catheter and positioned such that the sheath blocks one ormore auxiliary fluid inlet ports 3806 while leaving one or more primaryfluid inlet ports 3808 open. For example, the sheath 3802 can include afirst hole pattern 3810 that is aligned with the primary holes 3808, anda second hole pattern 3812 that is aligned with the auxiliary holes 3806only when the sheath is translated longitudinally relative to thecatheter 3800. When the primary ports 3808 become clogged or obstructed,the sheath 3802 can be advanced or retracted to expose one or more ofthe auxiliary inlet ports 3806. In the illustrated embodiment, thecatheter 3800 includes a bleed hole 3814 adjacent to the distal end ofthe catheter which allows the sheath 3802 to move when a pressuredifferential is applied thereto. In particular, the bleed hole 3814 canallow fluid beneath the sheath 3802 to escape to reduce any pressurebuildup that might prevent the sheath from advancing. In otherembodiments, the sheath 3802 can include one or more protrusions thatextend radially inward into the catheter. High pressure fluid flowgenerated by a flushing operation can exert a force on the protrusionswhich causes longitudinal translation of the sheath 3802 relative to thecatheter 3800 to open up one or more of the auxiliary ports 3806.Alternatively, the sheath 3802 can be translated mechanically, forexample by a lever or linkage system actuated by the flusher.

FIGS. 39A-39B illustrate another exemplary embodiment of a catheter3900. The catheter 3900 includes one or more fluid inlet ports 3902defined by conical flaps 3904 that normally extend radially inward fromthe sidewall 3906 of the catheter as shown in FIG. 39A. When the inletports 3902 become clogged or obstructed, a flushing operation can beperformed, which can cause the conical flaps 3904 to become invertedsuch that they extend radially outward from the exterior sidewall of thecatheter, as shown in FIG. 39B. Transitioning the flaps 3904 to theoutward position shown in FIG. 39B can be effective to dislodge anydebris that may be clogging or obstructing fluid flow through the inletports 3902.

FIGS. 40A-40B illustrate another exemplary embodiment of a catheter4000. The catheter 4000 is a split-tip catheter in which the first andsecond tips 4002, 4004 are initially joined together. One or more fluidinlet ports 4006 are formed in the joined surfaces of the tips 4002,4004 such that fluid cannot flow through the inlet ports 4006 while thetips are disposed in their initial, joined configuration. When one ormore other fluid inlet ports 4008 formed in the tips become clogged orobstructed, a flushing operation can be performed to separate thecatheter tips and expose the previously covered inlet ports 4006 torestore fluid flow through the catheter. The tips 4002, 4004 can bejoined by an adhesive 4010 configured to release the tips when thepressure applied by a flushing operation exceeds the bond strength ofthe adhesive. The type and the amount of the adhesive can thus beselected to control the pressure required to separate the tips of thecatheter. The tips of the catheter can also be separated along aperforation or frangible seam when the pressure applied by a flushingoperation exceeds the tensile strength of the perforation or seam.

FIG. 41 illustrates another exemplary embodiment of a catheter 4100. Thecatheter 4100 includes one or more degradable sheaths 4102 configured todegrade over time with exposure to fluid within a patient's ventricle.As the sheaths 4102 degrade, they expose auxiliary fluid inlet holes4104 that were previously covered by the sheaths. In the illustratedembodiment, a plurality of staggered sheaths 4102 are provided such thatthe sheath length gradually decreases from the innermost sheath to theoutermost sheath. As a result, degradation of only one sheath thicknessis required to expose the proximal-most auxiliary holes, whereasdegradation of four sheath thicknesses is required to expose thedistal-most auxiliary holes. The illustrated catheter 4100 is thusconfigured to gradually expose additional fluid inlet holes 4104 as timepasses (e.g., in a number of stages equal to the number of staggeredsheaths 4102, which stages can be spread over multiple days, weeks,months, etc.). In addition, one or more of the auxiliary holes 4104 canbe opened instantly (i.e., without waiting for the sheath 4102 todegrade) by performing a flushing operation. The resulting pressurespike in the catheter 4100 can cause one or more of the sheaths 4102 torupture (e.g., in a region where only a single ply of the sheathremains) to open the auxiliary holes 4104 disposed underneath.

FIG. 42 illustrates another exemplary embodiment of a catheter 4200. Thecatheter 4200 is a split-tip catheter having a primary tip 4202 and asecondary tip 4204 which each have one or more fluid inlet holes 4206formed therein. The secondary tip 4204 is initially rolled up on itselfand tacked such that the fluid inlet holes formed in the secondary tipare blocked by the adjacent rolled portions of the secondary tip. When aflushing operation is performed, or when a flushing operation isattempted and is unsuccessful in clearing the primary tip 4202, thefluid pressure in the catheter 4200 can increase until it exceeds thebond strength of the tack, thereby severing the tack and allowing thesecondary tip 4204 to unroll. Once unrolled, the fluid inlet ports 4206of the secondary tip 4204 are exposed and fluid can pass therethroughinto the interior of the catheter 4200.

FIGS. 43A-43B illustrate another exemplary embodiment of a catheter4300. A terminal distal tip 4302 of the catheter having one or moreauxiliary fluid inlet holes 4304 formed therein is initially folded inon itself and tacked to a more-proximal section 4306 of the catheter, asshown in FIG. 43A. One or more primary fluid inlet ports 4308 formed ina proximal section 4310 of the catheter are open to allow fluid to enterthe central lumen of the catheter. When one or more of the primary fluidports 4308 is blocked or obstructed, a flushing operation can beperformed to break the tack holding the folded-in portion 4302 of thecatheter and force the folded-in portion to unfold. As shown in FIG.43B, when the initially folded-in portion 4302 is unfolded, theauxiliary fluid ports 4304 formed therein are opened and fluid is freeto flow through the auxiliary fluid ports into the inner lumen of thecatheter. In some embodiments, the catheter 4300 can be a split-tipcatheter and one or both of the tips can have a folded-in auxiliaryportion.

FIGS. 44A-44B illustrate another exemplary embodiment of a catheter4400. The catheter 4400 includes an accordion or bellows portion 4402formed adjacent a distal end thereof in which one or more auxiliaryfluid inlet ports 4404 are formed. The bellows portion 4402 is initiallytacked in a folded position, as shown in FIG. 44A, such that theauxiliary fluid inlet ports 4404 are covered by adjacent folds of thebellows portion. When one or more of primary fluid inlet ports becomeblocked or obstructed, a flushing operation can be performed to breakthe tack holding the bellows portion 4402 in the folded position to openup the auxiliary fluid inlet ports 4404 and restore fluid flow throughthe catheter, as shown in FIG. 44B. In some embodiments, tacks ofvarying strength can be formed between successive folds of the bellowsportion 4402, such that each flushing operation is only effective tobreak the weakest remaining tack and expose the auxiliary ports formedin the corresponding fold of the bellows portion. In other words, afirst flushing operation can break a first tack to expose a firstauxiliary port. When the first auxiliary port becomes clogged, a secondflushing operation can break a second tack to expose a second auxiliaryport. This process can be repeated until all of the tacks are broken.The usable life of the catheter can thus be effectively extended by afactor equal to the number of tacks in the bellows portion. In someembodiments, the catheter can be a split-tip catheter and one or both ofthe tips can have a bellows portion.

FIG. 45 illustrates another exemplary embodiment of a catheter 4500. Thecatheter 4500 includes a plurality of primary fluid inlet ports 4502formed in a distal end thereof. The catheter also includes a pluralityof blind bores or non-full thickness penetrations 4504. In use, when theprimary fluid inlet ports 4502 are blocked, a pressure spike in thecatheter can be produced as the result of a flushing operation torupture the remaining material in the blind bores 4504, therebyconverting the blind bores into auxiliary fluid inlet ports andrestoring the flow of fluid through the catheter. The blind bores 4504can be formed to varying depths such that a tiered opening can beachieved with multiple successive flushes. In other words, the deepestbores can be opened in a first flushing operation. When those boresbecome clogged, the next-deepest bores can be opened in a secondflushing operation. This process can be repeated until all of the boreshave been opened.

FIG. 46 illustrates another exemplary embodiment of a catheter 4600. Thecatheter 4600 includes an arm 4602 that extends longitudinally throughthe inner lumen of the catheter. A plurality of fingers 4604 extendradially outward from the arm 4602. When any of the fluid inlet ports4606 formed in the catheter 4600 becomes blocked, a flushing operationcan be performed to advance and/or retract the arm 4602 such that thefingers 4604 push any obstructions blocking the inlet ports out of thecatheter. In an exemplary embodiment, depressing a dome portion of aflusher acts on a linkage to advance the arm 4602 longitudinally andallowing the dome to return to its un-collapsed configuration pulls thelinkage back to retract the arm longitudinally. This process can beperformed repeatedly to “brush” the fluid inlet ports 4606 with thefingers 4604, dislodging any debris that is blocking or clogging theinlet ports. The arm 4602 can also be translated hydraulically usingfluid pressure supplied to the catheter by a flushing operation.

FIG. 47A illustrates another exemplary embodiment of a catheter 4700.The catheter 4700 includes a plurality of primary inlet holes 4702formed at a distal tip end 4704 of the catheter configured to bedisposed within a patient's ventricle. While a single-lumen, single-tipcatheter is shown, it will be appreciated that the catheter can be amulti-lumen catheter and/or a multi-tip catheter. The primary holes 4702form pathways through which fluid external to the catheter 4700 canenter an inner lumen of the catheter. The catheter also includes asegment 4706 in which one or more slot-shaped auxiliary holes 4708 areformed. The auxiliary slots 4708 are initially blocked such that fluidexternal to the catheter 4700 cannot pass through the auxiliary slotsinto an inner lumen of the catheter. Rather, fluid can only pass throughthe auxiliary slots 4708 after they are forced open (e.g., by a flushingoperation of one of the flushers disclosed above). The auxiliary slots4708 are initially blocked by a membrane 4710. The membrane 4710 can beformed from a variety of implantable and biocompatible materials, suchas silicone or other silastic materials. The catheter 4700 can bemanufactured in various ways. For example, the slot(s) 4708 can beformed by making non-full-thickness punches into the side of thecatheter tubing. The slots can also be formed by punching all the waythrough the catheter tubing and then molding the membrane 4710 over orotherwise attaching the membrane to the catheter. By way of furtherexample, the section 4706 of the catheter in which the slot(s) 4708 areformed and the distal portion 4704 of the catheter in which the primaryinlet holes 4702 are formed can be molded as a single component. As yetanother example, the entire catheter 4700 can be molded as a singlecomponent.

As shown in FIG. 47B, the section of the catheter 4700 in which theauxiliary slot or slots 4708 are formed can be a separate molded part4706′ with inlet and outlet barbs 4712, 4714 for coupling the moldedpart to proximal and distal sections of the catheter 4700. The pop-outauxiliary holes or slots 4708 can thus be provided as an inlinecomponent for assembly with other portions of the catheter. In someembodiments, the molded part 4706′ can be formed from a differentmaterial (e.g., a stiffer or higher-durometer material) than theremainder of the catheter to provide additional support for the membrane4710. The molded part 4706′ can have an overall length of about 0.82inches and the cylindrical main body portion of the molded part can havea length of about 0.40 inches.

In some embodiments, the catheter tubing can have an inside diameter ofabout 0.050 inches and a thickness of about 0.030 inches such that theoutside diameter of the catheter is about 0.110 inches. In someembodiments, the distal portion of the catheter in which the primaryholes are formed can have a length of about 0.394 inches. In someembodiments, the diameter of the primary holes can be about 0.047inches. In some embodiments, the auxiliary slots can have a length L ofbetween about 0.050 inches to about 0.220 inches. In some embodiments,the auxiliary slots can have a width W of about 0.050 inches. In someembodiments, the membrane can have a thickness between about 0.001inches and 0.010 inches. The auxiliary slots can have any of a varietyof shapes. For example, the slots can be substantially rectangular withrounded corners as shown. Alternatively, the corners of the slot can besharper to make the corners burst more easily. In some embodiments, themembrane can include scoring 4716 to provide a seam or weakness alongwhich the membrane can tear. The membrane can be formed from any of avariety of materials, including silastic materials such as silicone,polyurethane, and the like. In some embodiments, the membrane can beconfigured to tear only when a pressure of at least about 10 psi to atleast about 25 psi or more is applied thereto.

FIGS. 48A-48D illustrate another exemplary embodiment of a catheter4800. The catheter 4800 includes a plurality of inlet holes 4802 formedat a distal tip end 4804 of the catheter configured to be disposedwithin a patient's ventricle. While a single-lumen, single-tip catheteris shown, it will be appreciated that the catheter can be a multi-lumencatheter and/or a multi-tip catheter. The inlet holes 4802 form pathwaysthrough which fluid external to the catheter 4800 can enter an innerlumen of the catheter. Slits 4806 can be formed in one or more of theinlet holes to allow the hole to deflect and open slightly when flushed,making it easier for any blockage 4808 disposed in the hole to breakfree and flush out of the catheter. In other words, the periphery of theinlet hole 4802 is configured to deform outwards when the catheter isflushed. FIG. 48B shows a hole 4802 with a cross-shaped slit 4806 undernormal operating pressure. As shown in FIGS. 48C-48D, when the pressureincreases beneath the hole 4802 during a flushing operation, the holeblossoms outwards along the slits 4806, expanding such that the blockage4808 can be cleared more easily. The inlet holes 4802 can have slits4806 oriented at any of a variety of angles. For example, the slits canbe horizontal, vertical, or can include perpendicularly-intersectinghorizontal and vertical slits as shown.

FIGS. 58A-58B illustrate an exemplary embodiment of a catheter 5800. Thecatheter 5800 includes a plurality of inlet holes formed at a distal tipend of the catheter configured to be disposed within a patient'sventricle. While a single-lumen, single-tip catheter is shown, it willbe appreciated that the catheter can be a multi-lumen catheter and/or amulti-tip catheter. For example, the catheter can be a dual lumencatheter with two independent lumens that extend the full length of thecatheter. By way of further example, the catheter can be a split-tipcatheter having first and second tips at the distal end that merge intoa single lumen that extends through the remainder of the catheter.

The plurality of inlet holes includes one or more primary holes 5802which form pathways through which fluid external to the catheter 5800can enter an inner lumen of the catheter. The plurality of inlet holesalso includes one or more auxiliary holes 5804 which are initiallyblocked such that fluid external to the catheter 5800 cannot passthrough the auxiliary holes into an inner lumen of the catheter. Rather,fluid can only pass through the auxiliary holes 5804 after they areforced open (e.g., by a flushing operation of one of the flushersdisclosed above). The auxiliary holes 5804 are initially blocked by amembrane 5806. In some embodiments, the membrane 5806 can be disposedover the exterior surface of the catheter 5800. The membrane 5806 can beformed from a variety of implantable and biocompatible materials, suchas silicone. The membrane 5806 can be stretched across the openings 5804and attached to the catheter 5800 under tension, such that penetrationof the membrane results in a tear in which opposed sides of the tearmove out of the way of the underlying hole. The membrane 5806 can bestretched over the auxiliary holes 5804 in a variety of directions ororientations, which can allow for the tear produced when the membrane isruptured to have some directionality (i.e., to define an opening thatfaces in a particular direction). The stretched membrane 5806 can beattached to the catheter 5800 in various ways. For example, the membrane5806 can be thermally welded to the catheter 5800 using a heat punch,mechanically coupled to the catheter using O-rings disposed around themembrane and the catheter, or molded into or onto the catheter. In someembodiments, a plurality of auxiliary holes can be provided, each havinga membrane stretched in a different direction. The thickness of themembrane, the degree of tension applied to the membrane, and thematerial from which the membrane is formed can be selected to controlthe force required to tear the membrane. In some embodiments, themembrane can be configured to burst at an opening pressure of about 5psi to about 15 psi. In some embodiments, the membrane is formed fromsilicone and has a thickness of about 0.001 inches.

The catheter 5800 can include a stiffening sleeve 5801 disposed over themembrane. The stiffening sleeve 5801 can include an opening 5803 that isaligned with the auxiliary hole 5804, and can be positioned in arecessed portion 5805 of the catheter such that the stiffening sleeveand the catheter define a continuous, smooth outer surface. Thestiffening sleeve 5801 can advantageously prevent the catheter 5800 frombending or ballooning under the pressure of a flushing cough while atthe same time focusing the cough pressure on the membrane 5806. Thecatheter 5800 can also include a bullet-tip plug 5809 that seals theterminal distal end of the catheter.

In some embodiments, the catheter 5800 can be manufactured by extrudinga silicone tube to form a catheter main body 5807 with the desiredinside and outside diameters. The tube can then be cut to the desiredlength. The distal portion 5811 of the catheter, including the recess5805 for the stiffening sleeve 5801, can then be formed on one end ofthe tube using a silicone overmolding process. Primary and auxiliaryholes 5802, 5804 can be added to this distal portion 5811 later in aseparate drilling step. Once the auxiliary hole 5804 is formed, asilicone membrane 5806 can be molded over the opening. Alternatively,the membrane 5806 and the auxiliary hole 5804 defined beneath themembrane 5806 can be formed simultaneously by molding them as onemonolithic, continuous part formed from silicone or other materials. Inother words, the auxiliary hole 5804 can be initially formed as anon-full-thickness or blind hole, with the remaining thickness definingthe membrane 5806. The stiffening sleeve 5801 can be formed from a PEEKextrusion and a laser cutting process can be used to form the window5803 in the stiffening sleeve. The stiffening sleeve 5801 can bepositioned over the membrane 5806 and bonded in place using RTV siliconeor the like. The distal plug 5809 can be molded as a separate siliconecomponent and then sealed to the distal end of the catheter using RTVsilicone of the like.

Any one or more components of the catheter 5800 can be formed from aradiopaque material or can have a radiopaque material embedded orimpregnated therein to facilitate visualization using various imagingtechniques. In some embodiments, barium sulfate or other radiopaquematerials can be molded into the distal portion 5811 of the catheter,the main body 5807 of the catheter, the stiffening sleeve 5801, themembrane 5806, and/or the distal tip 5809.

The catheter 5800 can include various features for facilitating adetermination as to whether the membrane 5806 has been opened using CT,X-ray, or other imaging techniques. For example, a thin ribbon ofradiopaque material can be printed on the membrane. When the membraneopens, radiographic images of the implanted catheter can show the ribbonof material being torn away or separated. The ribbon can be deposited orprinted on the membrane in an ultra-thin layer using nanotechnology. Theribbon can extend longitudinally, laterally, diagonally, or in any otherdirection or directions across the auxiliary opening, and can be formedin a matrix or any other pattern. FIG. 59A illustrates a catheter 5900having a thin ribbon 5913 of metal extending laterally across themembrane 5906 and held in place by the stiffening sleeve 5901. Theribbon can also be deposited as a series of dots or grid lines. As yetanother example, the membrane can be initially covered by a radiopaquewindow that pops out and floats away after the membrane bursts. Presenceor absence of the radiopaque window in images of the catheter can beused to determine whether the membrane has burst. By way of furtherexample, a radiopaque wire can be looped back and forth longitudinallyacross the auxiliary opening such that, when the membrane is opened, thewire stretches out of the opening to provide an indication inradiographic images that the membrane has burst. As shown in FIG. 59B,the wire 5915 can be disposed over the membrane 5906 of the catheter5900 and under the stiffening sleeve 5901 such that the ends of the wireremain attached to the catheter after the membrane bursts. In a stillfurther example, an antenna that resonates when excited with RF energycan be disposed over the membrane and can be configured to bend, break,or otherwise distort when the membrane bursts. Accordingly, the responsereceived from the antenna can be monitored or measured to detect changesin the response or ceasing of the response as an indication that themembrane has burst.

In use, the catheter 5800 is implanted in a patient with the distal tipof the catheter disposed in the patient's ventricle. Fluid enters theprimary holes 5802 of the catheter and flows through the inner lumen ofthe catheter to a downstream portion of the shunt system (e.g., aflusher, a valve, and/or a drain catheter). When the primary holes 5802become clogged or obstructed (e.g., as shown in FIG. 60A), or at anyother time a user so desires, a flusher can be actuated to deliver apressurized cough of fluid through the inner lumen of the catheter. Thecough of fluid can dislodge obstructions 5808 from the clogged primaryholes 5802 (e.g., as shown in FIG. 60B) and/or cause the membrane 5806covering one or more auxiliary holes 5804 to burst (e.g., as shown inFIG. 60C). In other words, flushing the catheter can open the auxiliaryinlet ports 5804 to provide a secondary fluid pathway into the catheter,e.g., when the primary fluid pathway becomes clogged or obstructed.

FIG. 61 illustrates one exemplary embodiment of a shunt system 6100 thatincludes the flusher 4900 of FIGS. 49A-49G and the catheter 5800 ofFIGS. 58A-58B. The ventricular catheter 5800 extends from an anchor 6102which is coupled to the upstream port of the flusher 4900. Thedownstream port of the flusher is connected to a shunt valve 6104, whichis in turn coupled to a drain catheter 6106. In some embodiments, theshunt system 6100 can be used to treat hydrocephalus by implanting theventricular catheter 5800 such that a distal end of the catheter isdisposed within a brain ventricle 6110 of a patient 6112. The anchor6102 can be mounted to the patient's skull, beneath the skin surface,and the drain catheter 6106 can be implanted such that the proximal endof the drain catheter is disposed within a drain site, such as theabdominal cavity. The valve 6104 can be configured to regulate the flowof fluid from the ventricle 6110 to the drain site. For example, whenfluid pressure in the ventricle exceeds the opening pressure of thevalve 6104, the valve can be configured to open to allow excess fluid todrain out of the ventricle 6110. When the fluid pressure drops to anacceptable level, the valve 6104 can be configured to close, therebystopping further draining of fluid. The flusher 4900 can be actuated asdescribed above to clear obstructions from the shunt system (e.g., fromthe primary openings of the catheter 5800). Alternatively, or inaddition, the flusher 4900 can be actuated to open one or more auxiliaryflow paths through the shunt system (e.g., by popping open the membraneof the catheter 5800).

Although the invention has been described by reference to specificembodiments, it should be understood that numerous changes may be madewithin the spirit and scope of the inventive concepts described.Accordingly, it is intended that the invention not be limited to thedescribed embodiments, but that it have the full scope defined by thelanguage of the following claims.

1. A flusher comprising: a body that defines a collapsible flush dome; apassive flow path that extends between an upstream port and a downstreamport, at least a portion of the flow path being defined by a pinch tubethat extends across an exterior surface of the flush dome; and a valvehaving a first position in which the flush dome is not in fluidcommunication with the upstream port or the passive flow path and asecond position in which the flush dome is in fluid communication withthe upstream port and the passive flow path; wherein application of aforce to the pinch tube is effective to collapse the pinch tube to blockthe passive flow path and to collapse the dome to move the valve to thesecond position and flush fluid through the upstream port.
 2. Theflusher of claim 1, wherein the valve comprises a valve body that iscompressed against a valve seat by an adjustment disc such that rotationof the adjustment disc is effective to change a threshold openingpressure of the valve.
 3. The flusher of claim 2, wherein the adjustmentdisc is threadably mounted in a valve cartridge in which the valve bodyis disposed.
 4. The flusher of claim 1, wherein at least a portion ofthe flush dome is defined by a refill plate having a refill valvemounted therein.
 5. The flusher of claim 4, wherein the refill valve hasa first position in which the passive flow path is not in fluidcommunication with the flush dome and a second position in which thepassive flow path is in fluid communication with the flush dome.
 6. Theflusher of claim 5, wherein collapsing the flush dome is effective tohold the refill valve in the first position.
 7. The flusher of claim 4,wherein the refill plate mechanically interlocks with the body.
 8. Theflusher of claim 4, wherein the refill plate defines an outer lip thatis received within a recess formed in the body such that the lip issurrounded on at least four sides by the body.
 9. The flusher of claim1, wherein a flush channel extending between the flush dome and thevalve includes a connection formed by a barbed fitting.
 10. The flusherof claim 1, further comprising a ventricle catheter in fluidcommunication with the upstream port.
 11. The flusher of claim 10,wherein the catheter comprises: a primary fluid inlet port through whichfluid external to the catheter can flow into an inner lumen of thecatheter; an auxiliary fluid inlet port covered by a membrane such thatfluid external to the catheter cannot flow through the auxiliary inletport; wherein the membrane is configured to rupture when a predeterminedthreshold force is applied to the membrane by fluid in the inner lumenof the catheter to open the auxiliary fluid inlet port and allow fluidto flow therethrough.
 12. The flusher of claim 11, wherein the auxiliaryfluid inlet port comprises a rectangular slot with rounded corners. 13.The flusher of claim 11, further comprising a stiffening sleeve disposedover the membrane.
 14. The flusher of claim 13, wherein the stiffeningsleeve includes a window that is aligned with the auxiliary fluid inletport of the catheter.
 15. The flusher of claim 13, wherein thestiffening sleeve is mounted in a recess formed in the catheter suchthat the outer surface of the stiffening sleeve sits flush with theouter surface of the catheter.
 16. A flusher comprising: a body thatdefines a collapsible flush dome; a passive flow path that extendsbetween an upstream port and a downstream port; and a valve comprising avalve body compressed against a valve seat by a threaded adjustmentdisc, the valve having a closed position in which the flush dome is notin fluid communication with the upstream port via the valve and an openposition in which the flush dome is in fluid communication with theupstream port via the valve; wherein a threshold pressure required totransition the valve from the closed position to the open position isadjustable by rotating the threaded adjustment disc with respect to thebody.
 17. A method of flushing a shunt system, comprising: in a singlemotion, applying a force to a flusher at a single contiguous contactarea to collapse a flush dome of the flusher and to close off aconnection to a downstream portion of the shunt system; whereincollapsing the flush dome is effective to release a cough of pressurizedfluid through an upstream portion of the shunt system.
 18. The method ofclaim 17, wherein the cough of fluid clears an obstruction from acatheter in fluid communication with the flusher.
 19. The method ofclaim 17, wherein the cough of fluid opens an auxiliary flow paththrough a catheter in fluid communication with the flusher.